XFX MERC 310 RX 7900 XT Review: AMD’s Back in the Game


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XFX MERC 310 RX 7900 XT Black Edition
XFX MERC 310 RX 7900 XT Black Edition

Thanks to XFX, we have the MERC 310 BLACK RX 7900 XT on the test bench today and is also our first GPU from AMD’s RDNA3 line of cards. The new RX 7900 XT is based on the NAVI 31 die and according to AMD, their new design delivers nearly 1.5x the performance per watt. With the new GPUs from AMD, we see a new approach (well, sort of) using a chiplet design. There are some similarities to the ZEN processors, but using chiplets on a GPU is very different compared to a CPU. We’ll try and break this down into more detail below and cover the features of the XDX MERC in our hands.

The MERC 310 RX 7900 XT brings a robust VRM design, a large aluminum triple-fan shroud with a plated copper heatsink, and an overclock out of the box. The 2.7-slot cooling solution includes an LED on the card’s facing edge showing the “XFX” logo. A full-length aluminum backplate cleans up the card’s backside while adding rigidity and heat dissipation. Overall, it’s a beautiful card and fits well with most build themes.

Performance-wise, this overclocked card performed well in our testing, besting the last generation RTX 3090 Ti and was ahead of the RTX 4080 in some tests or close behind in most. This card would be ideal for high-refresh FHD (1920 x 1080) and more than able to handle 144 Hz WQHD (2560 x 1440) screens. In our 4K UHD testing, the RX 7900 XT proved very capable, scoring 90 FPS or better across all benchmarks.

The MSRP for the XFX MERC 310 RX 7900 XT Black Edition is set at $949.00, a $50 premium over the 7900 XT reference model’s MSRP of $899.99. This premium has benefits: a factory overclock, improved power delivery, solid aluminum construction, a premium copper-based vapor chamber cooling solution, and a three-year warranty.

Since this is a new architecture launch, we need to discuss RDNA 3 and AMD’s new chiplet design; this may get a bit dry, so grab a coffee and settle in.

RDNA3 Chiplet Design

Chiplet
Chiplet Design
Image Courtesy of AMD

AMD uses a similar approach for NAVI 31 and the Zen CPU, separating the memory/IO portion from the computational part of the die. Zen4 CPUs contain a large Input/Output Die (IOD) manufactured on TSMC N6 that connects to the system memory and PCIe interface. This IOD is connected via the Infinity Fabric to one or two much smaller Core Compute Dies (CCD) manufactured using TSMC N5. Specific processes, such as memory interfaces and Cache, don’t scale performance-wise when shrinking nodes. On top of this, the TSMC N5 is more costly to produce than TSMC N6 leading AMD to mix processes in the CPUs for efficiency and cost reasons.

Chiplet Technology
Chiplet Technology
Image Courtesy of AMD

CPUs and GPUs are very different in how they function and communicate with the memory and the rest of the system. Typically CPUs have a limited number of cores when compared to GPUs. Take the Ryzen 9 7950X, for example, with 16 cores and 32 threads; this is a drop in the bucket compared to the RX 7900 XTX with 96 CUs for a total of 6,144 Stream Processors. Feeding all these cores takes an enormous amount of memory bandwidth.

Chiplet Connection
Chiplet Connection
Image Courtesy of AMD

To accommodate this bandwidth, AMD took an opposite approach with a larger Graphics Compute Die (GCD) housing thousands of Stream Processors, video codec hardware, display interfaces, and the PCIe connection. Connected to the GCD are up to six smaller Memory Controller Dies (MCD) containing the large Infinity Cache, Infinity Fabric links, and GDDR6 memory controllers. The GCD measures 300 square millimeters and contains 45.7 Billion transistors. Each MCD measures 37 square millimeters with 2.05 Billion transistors. In the specifications chart, the transistor count combines the GCD + MCD.

AMD still had another hurdle in their GPU chiplet design. The Infinity Fabric that AMD uses in their CPUs works well, but scaling it up to accommodate a 384-bit interface would consume too much power to make it feasible.

Infinity Fanout Links
Infinity Fanout Links
Image Courtesy of AMD

AMD needed a replacement for their organic substrate interconnect and developed something completely new, the Infinity Fanout Links. This new tech from AMD packs double the number of connections in less than 2% of the same area as the Infinity Fabric used. These links operate at 9.2 Gb/s, offering ten times the bandwidth of AMD’s Infinity Fabric for an industry-leading 5.3 TB/s. These links also account for less than 5% of the total GPU power consumption, thanks to AMD’s innovation.

RDNA 3 Architecture

RDNA 3 Improvements
RDNA 3 Improvements
Image Courtesy of AMD

On top of a total GPU redesign to accommodate the chiplet layout, AMD has also made improvements to most, if not all, aspects of its architecture. The compute units, Cache, and Ray tracing have all seen some tweaking. According to AMD, RDNA 3 GPUs can hit the same frequency as RDNA 2 while using half the power or 1.3 times the frequency while using the same power.

Although the official boost speeds seem modest, AMD claims that RDNA 3 has been created to reach speeds of 3 GHz. During our testing, we did see some peaks over the 3 GHz mark, but the card doesn’t run at that speed continuously.

Compute Unit Enhancements
Compute Unit Enhancements
Image Courtesy of AMD

Like the previous Generation, RDNA3 uses Compute Unit pairs, but the new generation has some significant changes. Aside from the 20% increase in Compute units over RDNA 2, we also have updates to the L0/L1/L2 cache sizes, more SIMD32 registers for FP32 and matrix workloads, plus wider and faster interfaces.

Looking at the scheduler for RDNA 3, we now have double the floating point 32 and Matrix SIMD 32 instruction capability. This should give RDNA 3 GPUs double the raw FP32 throughput of RDNA2. We should also see double the AI Matrix throughput, although resources are shared with FP32 instructions. New to the AI units is BF16 (brain-float 16-bit) support, as well as INT4 WMMA Dot4 instructions (Wave Matrix Multiply Accumulate); AMD claims there’s an overall 2.7x increase in matrix operation speed.

RDNA 3 Cache System
RDNA 3 Cache System
Image Courtesy of AMD

The Cache system for RDNA 3 has seen a complete overhaul as well. Compared to RDNA 2, the L0 cache has doubled to 32 KB, the L1 Cache has also doubled to 256 KB, and the L2 Cache is now up to 6 MB compared to 4 MB from the last generation. The L0, L1, and L2 Cache links are also 1.5x wider than RDNA 2, improving the bandwidth.

The L3 (Infinity Cache) has shrunk compared to the last gen. It’s also divided up between the MCDs in 16 MB chunks. The RX 7900 XTX with six MCDs would see the maximum Infinity Cache of 96 MB. The 7900 XT we have here today has 80 MB of Infinity Cache. The second generation can deliver up to double the bandwidth, 3494.4 GB/s for the RX 7900 XTX, compared to 1793.5 GB/s over the last generation’s RX 6950 XT.

2nd Generation Ray Tracing
2nd Generation Ray Tracing
Image Courtesy of AMD

AMD’s RDNA 3 Compute Units evolve their high-performance ray tracing acceleration with several hardware and software optimizations. They employ methods to skip parts of the acceleration structure during transversal to execute the workload efficiently. An enhanced cache structure allows more rays to be in flight for faster performance. Overall, thanks to the new optimizations, higher frequencies, and increased number of Ray Accelerators, AMD says RDNA 3 should deliver up to a 1.8x the performance for ray tracing compared to RDNA 2.

Also, with RDNA 3, we see the introduction of AMD’s new Radiance Display Engine featuring the industry’s first Display Port 2.1 interface in a high-performance graphics card. Display Port 2.1 has a display link bandwidth of 54 Gbps doubling the display bandwidth per port over RDNA 2, supporting unprecedentedly high refresh rates.

Radiance Display
Radiance Display
Image Courtesy of AMD

Specifications and Features

AMD Radeon RX Series Specifications
ModelAMD Radeon
RX 7900 XTX
XFX MERC 310 RX 7900 XTAMD Radeon RX 6900 XT
GPUNavi 31Navi 31Navi 21
ArchitectureRDNA3RDNA3RDNA2
ProcessTSMC N5 + N6TSMC N5 + N6TSMC 7 nm
Transistors58 Billion56 Billion26.8 Billion
Infinity Cache96 MB80 MB128 MB
Compute Units968480
Ray Accelerators968480
Stream Processors614453765120
ROPs/TMUs192/384192/336128/320
Game Clock2269 MHz2220 MHZ2015 MHz
Boost Clock2500 MHz2560 MHz2250 MHz
Memory24 GB GDDR620 GB GDDR616 GB GDDR6
Memory Speed20 Gbps GDDR620 Gbps GDDR616 Gbps GDDR6
Memory Bandwidth960 GB/s800 GB/s512 GB/s
Memory Interface384-bit320-bit256-bit
Throughput (FP32)61.4 TFLOPs51.6 TFLOPs20.6 TFLOPs
TDP (Watts)355 W300 W300 W
Release Date12/13/202212/13/202212/18/2021
MSRP (USD)$999.00$899.00$999.00

The XFX MERC 310 RX 7900 XT BE uses the Navi 31 core measuring 300 mm2 with 47.5 billion transistors. The XT variant of the RX 7900 offers 5,376 stream processors, 192 ROPs, and 336 TMUs, slightly less than the RX 7900 XTX. The 7900 XT also has 80 MB of AMD’s second-generation Infinity cache with 20 GB of GDDR6 running at 20 Gbps over a 320-bit bus for 800 GB/s total bandwidth.

Typically, the difference between the reference cards and AIBs is the cooler, power delivery, and clock speeds. In this case, the MERC 310 BLACK is spec’d at 2220 MHz Game Clock and 2560 MHz Boost Clock, which is the same as the reference design. The game clock is where AMD says the card will run most of the time but checking our results in the synthetic benchmarks; the Merc 310 7900 XT ran at or above the boost clock consistently.

XFX’s Speedster lineup for the RX 7900 XT cards is unknown because of NDAs. I’m confident, as usual, there will be multiple GPUs available at different trim levels.

Our XFX RX 7900 XT is the MERC 310 Black Edition which uses the 310 heatsink – equipped with three 100 x 15 mm fans. The new 13-blade fans are designed for high efficiency and longer life thanks to the dual ball bearings and blade shape. This combination of three fans delivers high airflow and low noise during stock operation. Once we overclocked this GPU, we tested the fans at full speed (3300 RPM), which was quite loud. Luckily when left at auto, they never reached these speeds very often.

XFX also redesigned the heatsink to improve airflow dynamics and cooling efficiency. The premium 2.7-slot aluminum heatsink has 913,966 square mm of surface area for maximum heat dissipation. We also have a full plated-copper heat spreader, vapor chamber, and six 6 mm heat pipes that snake through the heat sink. Additionally, that card uses a lot of high-quality thermal tape, aiding in thermal transfer from the core, memory, and power bits. In our cooling tests, the MERC 310 RX 7900 XT BE peaked at 58°C under load at stock speeds and was quiet.

XFX doesn’t have any additional software for overclocking, but Radeon Adrenalin works fine, and third-party utilities such as MSI afterburner for tweaking the core and memory speeds. The MERC 310 doesn’t include any controllable RGB LEDs but has a subtle backlit LED light bar​​ showing the XFX logo.

XFX MERC310 Black RX 7900 XT Backplate
XFX MERC310 Black RX 7900 XT Backplate

SOLID BACKPLATE

In addition to protecting the card, the solid aluminum
backplate is being utilized as an additional heat spreader.
Thermal pads have been added to critical locations on
the backside of the PCB to transfer heat to the
backplate. The backplate also features 33% more
surface area when compared to the MERC319 6950
XT backplate

XFX MERC310 Black RX 7900 XT PWM
XFX MERC310 Black RX 7900 XTX PWM

FULL DIGITAL PWM POWER DELIVERY

The XFX MERC 310 7900 XT Black utilizes a 13+1 phase design. The default BIOS delivers 290 watts of power to the GPU.

(a total of 20 thermal pads).
XFX MERC310 Black RX 7900 XT Cooling

Vapor Chamber and Thermal Pads

The nickel-plated copper vapor chamber is utilized for
both GPU and GDDR6 modules. XFX utilizes a thorough
placement of thermal pads across all GDDR, VRM, and
other vital components, including the backside of the PCB
(a total of 20 thermal pads).

XFX MERC310 Black RX 7900 XTX Vapor Chamber
XFX MERC310 Black RX 7900 XT Vapor Chamber

Vapor Chamber and Heatpipes

Plated Copper heat sink with a vapor chamber and six 6 mm Heatpipes offer tremendous cooling across GPU and memory.

XFX MERC310 Black RX 7900 XTX Fans
XFX MERC310 Black RX 7900 XT Fan Design

TRIPLE FAN DESIGN

13 Blade High-Efficiency Dual Ball Bearing Fans

three 100 mm x 15 mm fans

XFX MERC308 Black RX 6600 XT Design
XFX MERC310 Black RX 7900 XT Design

IT’S MORE THAN JUST DESIGN

Every iteration isn’t just designed for design’s sake; we take everything we learned from the last model and fine-tune, adjust, and modify it to make our GPU design as honest as possible—nothing fancy or unnecessary; just what is needed to increase performance and improve quality.

Retail Packaging and Accessories

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Retail packaging for the XFX MERC 310 RX 7900 XT has a vertical theme. It includes the XFX branding and MERC 310 model on the front with some features (Ray Tracing support, 20 GB VRAM, PCIe 4.0). Turning the package around offers a picture of the card and a more extensive list of features.

Inside the box, the card sits snug in form-fitting foam to keep it secure during shipping. The card is wrapped in an anti-static bag, and there are no included accessories besides the “Z” Bar support bracket pictured above.

This support bracket is included to help support the weight of this larger graphics card. The frame is fixed to the rear of the card, and the case with screws.

Z Bar Support System
Z Bar Support System

 

Meet the XFX Speedster MERC 310 RX 7900 XT Black Edition

XFX MERC310 Black RX 7900 XT
XFX MERC310 Black RX 7900 XT

The XFX MERC 310 Black RX 7900 XT has a clean and neat appearance. Most of the card is black, with some brushed aluminum accents around the edges. The three fans also have a brushed aluminum ring with a half-moon-type logo on the hubs. As mentioned, the MERC 310 has some backlighting on the outer edge where we have a white XFX logo. XFX has also included an Aluminum backplate with lots of thermal tape, offering excellent heat dissipation, PCB protection, and rigidity. The MERC 310 shouldn’t have any issues fitting in with most build themes.

XFX MERC310 Black RX 7900 XT
XFX MERC310 Black RX 7900 XT

XFX MERC310 Black RX 7900 XT
XFX MERC310 Black RX 7900 XT

XFX MERC310 Black RX 7900 XT
XFX MERC310 Black RX 7900 XT

XFX MERC310 Black RX 7900 XT
XFX MERC310 Black RX 7900 XT

XFX MERC310 Black RX 7900 XT
XFX MERC310 Black RX 7900 XT

XFX MERC310 Black RX 7900 XT
XFX MERC310 Black RX 7900 XT

A Closer Look at the XFX MERC 310 Black RX 7900 XT

Zooming in on the I/O layout, we’re greeted by three DisplayPorts (v2.1) and a single HDMI (v2.1) port—the latter supporting up to [email protected] The card’s maximum resolution is 8K (7680 x 4320) @ 165 Hz. While the card does not exhaust air directly out of the I/O plate, there are holes to let some warm air out. Power is sent to the GPU through two 8-pin PCIe connectors. Combined with the PCIe slot, the card provides up to 375 W of in-spec power, more than enough for this 315 W (TBP) card even while overclocked. Next to the PCIe power connectors is a dual-position BIOS switch. According to XFX, the position closest to the IO shield is the total power 290 W (TGP), while the other is a “Quiet” BIOS.

XFX MERC310 Black RX 7900 XT I/O Ports
XFX MERC310 Black RX 7900 XT I/O Ports

XFX MERC310 Black RX 7900 XT Power Connector
XFX MERC310 Black RX 7900 XT Power Connector

XFX uses a premium aluminum heatsink on this MERC 310 RX 7900 XT. The 2.7-slot solution uses six 6 mm heat pipes, with a total length of almost 2 meters, soldered to a plated copper vapor chamber which contacts the GPU die and memory ICs. We also have three 100 mm, 13-blade dual ball bearing fans to push plenty of air through the heatsink contained in a solid aluminum shroud that adds rigidity and aids in heat dissipation. This cooling solution pushes the card’s dimensions to 13.5 x 5.04 x 2.17 inches (344 x 128 x 55 mm).

XFX MERC310 Black RX 7900 XT Heat Sink
XFX MERC310 Black RX 7900 XT Heat Sink
XFX MERC310 Black RX 7900 XT Backplate
XFX MERC310 Black RX 7900 XT Backplate

The pictures above and below are the thermal tape that XFX has added to help cool the GPU die, MOSFETs, chokes, and memory ICs.

After entirely removing the heatsink, we can finally see the PCB. We see an unmarked Navi 31 silicon and its 522 mm² combined die area. Surrounding the GPU are 10 Hynix memory ICs (Hynix H56G42AS8) specified to run at 20 Gbps. The memory uses a 2-phase design with an 8-phase Monolithic Power Systems MP2856 controller feeding MP87997 70A MOSFETs. The GPU core is controlled via a 12-phase Monolithic Power Systems MP2857 and ten MP87997 70 A MOSFETs. There are three additional phases for the SOC using the same MOSFETs and an MP2856 controller. This is how they come up with a 13+1 phase design.

XFX MERC310 Black RX 7900 XT PCB Layout
XFX MERC310 Black RX 7900 XT PCB Layout
XFX MERC310 Black RX 7900 XT PCB Layout
XFX MERC310 Black RX 7900 XT PCB Layout

​Below are closeups of the power bits, Hynix GDDR6, and the control ICs.

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Below is a screenshot of GPU-Z showing the clocks we achieved at stock speeds. Out of the box, the MERC 310 RX 7900 XT has a listed game clock of 2225 MHz, with the boost clocks to 2550 MHz. The card ran fairly consistently around 2600 MHz during more challenging benchmarks and, as you can see below, boosted above 2900 MHz at times.

GPUz Stock
GPUz Stock

XFX MERC 310 RX 7900 XT Black Edition on the test bench…

XFX MERC310 Black RX 7900 XT
XFX MERC310 Black RX 7900 XT

 

Test System and Benchmark Methods

Test System Components
MotherboardMSI MEG z690 ACE
CPUIntel i9-12900K
CPU CoolerEK Predator 360 AIO
Memory2×16 GB G.Skill Trident Z5 Neo 6000 MHz CL30-38-38-96
SSDGigabyte Aorus 2 TB NVMe Gen4 (OS + Applications)
Power SupplyEVGA 750 W G3
Video CardXFX MERC 310 RX 7900 XT Black Edition/  Adrenalin 22.40.00.57

 

Our test system is based on the latest (at the time of publishing) mainstream Intel z690 platform and uses the i9-12900K 8P,8E/24t CPU. The DRAM is in a 2×16 GB configuration at 6000 MHz with CL30 timings, a middle-of-the-road option balancing performance, and cost. The CPU runs stock.

Since the last update, we have added a few new titles and dropped some older games. More details can be found in the GPU Testing Procedure article, which we have updated with our latest benchmarks. Below is a quick summary for easy reference.

  • UL 3DMark Time Spy – Default settings
  • UL 3DMark Fire Strike (Extreme) – Default settings
  • UL 3DMark Port Royal – Default Settings (Ray Tracing capable cards only)
  • Unigine Superposition – Performance, 1080p High
  • Shadow of the Tomb Raider – DX12, “Highest” preset
  • The Division 2 – DX12, Ultra preset, VSync Off
  • Assassin’s Creed: Odyssey – Ultra High preset, VSync Off
  • Far Cry 6 – Ultra defaults
  • F1 2021 – DX12, Very High defaults, Bahrain track
  • Metro: Exodus – DX12, Ultra defaults

Synthetic Benchmarks

Our first set of benchmarks hails from Underwriters Laboratories, which acquired Futuremark in 2014. Earlier in 2018, a rebrand occurred, and since that time, Futuremark is now UL. The benchmarks have not changed, just the name. We chose to stick with 3DMark Fire Strike (Extreme) and 3DMark Time Spy as these tests give users a good idea of performance on modern titles. We also include 3DMark Port Royal as a Ray Tracing benchmark.

3DMark Fire Strike (Extreme) is a DX11-based test that runs at 1080p resolution. UL says the graphics are rendered with detail and complexity far beyond other DX11 benchmarks and games. 3DMark Time Spy is a DX12 benchmark designed for Windows 10 PCs. It supports new API features such as asynchronous computing, explicit multi-adapter, and multi-threading and runs at 2560×1440. 3DMark Port Royal is the first Ray Tracing benchmark designed for Windows 10 PCs and graphics cards with Microsoft DirectX Raytracing capabilities.

3DMark Time Spy Results
3DMark Time Spy Results
3DMark Fire Strike Extreme Results
3DMark Fire Strike Extreme Results
3DMark Port Royal Results
3DMark Port Royal Results
Unigine Superposition Results
Unigine Superposition Results

Looking at the charts above, the XFX MERC 310 RX 7900 XT is holding its own in 3DMark’s Fire Strike Extreme and Time Spy compared to the RTX 4080. The RX 7900 XT falls behind all the RTX 4000 cards in Port Royal, a Ray Tracing benchmark, but the RX 7900 XT is ahead of the RTX 3090 and is showing a 50% gain compared to the last generation RX 6900 XT. Just as Fire Strike Extreme seems AMD-friendly, Unigine’s Superposition is the opposite, with the XFX MERC 310 RX 7900 XT slipping behind the RTX 4080.

Gaming Benchmarks

We have updated our testing suite for gaming benchmarks to bring more modern titles into the mix. Gone are Battlefield V, F1 2020, Far Cry: New Dawn, AOTS:e, and World of Tanks, which have been replaced with Metro Exodus, Assassin’s Creed: Odyssey, F1 2021, and Far Cry 6. We kept The Division 2 and Shadow of the Tomb Raider. The games should provide a good view of the card’s overall performance. Many of these are DX12 games.

1920 x 1080 (1080p) Results

Assassin's Creed Odyssey Results 1080p
Assassin’s Creed Odyssey Results 1080p
The Division 2 Results
The Division 2 Results 1080p
F1 2021 Results 1080p
F1 2021 Results 1080p
Far Cry 6 Results 1080p
Far Cry 6 Results 1080p
Metro: Exodus Results 1080p
Metro: Exodus Results 1080p
Shadow of the Tomb Raider Results 1080p
Shadow of the Tomb Raider Results 1080p

The XFX MERC 310 RX 7900 XT ran a tight race with the rest of the pack throughout most of our testing. Aside from Assassin’s Creed: Odyssey, the RX 7900 XT put on a great show, finishing at or near the top, even without the overclock.

2560 x 1440 and 4K UHD Results

Below are the higher resolution results starting with 2560 x 1440 and gaining in popularity, 3840 x 2160 (4K UHD). These resolutions are a bit of a stretch for lower-end cards, but the XFX MERC 310 RX 7900 XT proves it is more than capable of 4 K gaming.

2560 x 1440 WQHD Results
2560 x 1440 WQHD Results
3840 x 2160 4K UHD Results
3840 x 2160 4K UHD Results

Moving up in resolution, the XFX MERC 310 RX 7900 XT is losing ground to the Ada Lovelace cards from Nvidia. The 7900 XT performs well, maintaining 90 FPS or better throughout all of our 4 K tests, even besting the RTX 4080 in a couple of AMD-friendly titles, but it appears as the resolutions go up, the 7900 XT starts to fall behind a bit.

Ray Tracing and FSR Testing

Below, we tested Far Cry 6 with ray tracing at 1440p and 4K. The XFX MERC 310 RX 7900 XT performed very well here, but FC6 is an AMD title, so this is to be expected. One thing to note is the improvement made over the last generation RX 6900 XT. Comparing the 4K results, the RX 7900 XT shows a 50% gain over the 6900 XT.

We have also included FidelityFX Super Resolution results to give you an idea of the performance improvement it can offer.

Overclocking the XFX MERC 310 RX 7900 XT Black Edition

XFX doesn’t offer an overclocking utility, so we used the Adrenalin Tuning software in AMD’s Catalyst Control Center. The newer AMD cards operate in a highly dynamic way, and as such, there is no way to set a “static” operating frequency with their overclocking software. Instead, we have a lower and upper range setting for the GPU frequency. We also have sliders for adjusting the VRAM frequency and power levels and fine-tuned fan controls for custom cooling settings.

Radeon Adrenalin Overclocking Control Panel
Radeon Adrenalin Overclocking Control Panel

Using AMD’s Radeon software, we set out to overclock the MERC 310 RX 7900 XT. Overclocking this card took more time than expected. Typically when overclocking, you raise the frequencies until the GPU gets unstable. Stability didn’t seem to be an issue – performance was. We could raise the lower frequency limit to 2900 MHz, and the card would still run, and it also “appeared” to run at that speed when checking 3DMark logs. However, the resulting scores were terrible, typically worse than stock operation. This took a bit of time and extensive testing to settle on a minimum frequency level of 2704 MHz. We also added 100 MHz to the memory speed to finish our overclocked settings.

3DMark Fire Strike Extreme Overclocked Results
3DMark Fire Strike Extreme Overclocked Results

3DMark Time Spy Overclocked Results
3DMark Time Spy Overclocked Results

3DMark Time Spy Overclocked Results
3DMark Time Spy Overclocked Results

Unigine Superposition Overclocked Results
Unigine Superposition Overclocked Results

 

The XFX card peaked at 3079 MHz and consistently ran around 2750 MHz during most synthetic benchmarks. This shows the variance in overclocking the new NAVI 31; the core speed is very dependent on the load. In the end, this overclock gave us about a 3-5% increase in performance which was consistent throughout most of our benchmarks.

GPUz Overclocked
GPUz Overclocked

Temperatures and Power Use

We test power consumption by running through the game benchmarks of Shadow of the Tomb Raider and F1 2021 at stock speeds and while overclocked. We monitor temperatures throughout this testing, with the peak temperature listed in the data below. The benchmarks are extended (time) to allow the card to settle to simulate actual gaming conditions more accurately.

Temperatures on the XFX MERC 310 RX 7900 XT peaked at 58°C in F1 2021 and 56°C SOTR at stock settings. After overclocking the card, temperatures increased slightly in each game, peaking at 60°C for both titles. These excellent results demonstrate just how well XFX’s cooling solution works. The fans ramped up slowly, then settled at 50% (1600 RPM) when overclocked and were barely audible over the rest of the system.

XFX MERC 310 BLACK RX 7900 XT Temperature Results
XFX MERC 310 BLACK RX 7900 XT Temperature Results

Power use for the XFX MERC 310 RX 7900 XT peaked at 582 W (total system power) at stock, reaching 644 W while overclocked (both in SOTR). A quality 850 W power supply for most systems will be adequate for your needs, even while overclocking the card and CPU.

XFX MERC 310 BLACK RX 7900 XT Power Usage
XFX MERC 310 BLACK RX 7900 XT Power Usage

Conclusion

Once again, AMD has gambled with a new approach, stepping outside of the box, and that appears to have paid off for them. Applying a chiplet design to a GPU raised its own issues, such as data transfer and memory bandwidth. Using multiple MCDs solved the bandwidth issue, but data transfer between dies required something completely new, and AMD came through again with their Infinity Fanout links. Overall, their design has paid off. They wanted a high-performance graphics card for under a thousand dollars, and that’s precisely what they have.

The RX 7900 XT was close to but not quite up to the performance level of the RTX 4080, but it also comes in $300 less, assuming MSRP holds and retail prices don’t skyrocket as we’ve seen in the recent past. Comparing the 7900 XT to its predecessor, the 6900 XT, we see a massive leap in raw performance and considerable gains in the Ray Tracing arena.

XFX’s MERC 310 RX 7900 XT takes AMD’s reference design and puts its own mark on it. The MERC 310 version has a 13+2+1-phase power delivery system and 375 W of available power from the two 8-PCIe connectors. The heatsink is effective and quiet, with an appealing appearance overall. The XFX MERC 310 RX 7900 XT is a big card measuring 344 mm (13.5″) long, so always check your dimensions before purchasing. The drawback to having these features is a meager price increase. The reference model AMD RX 7900 XT’s MSRP is $899, and XFX’s MERC 310 will run you $949, a modest increase of $50 over the reference MSRP.

XFX has done a great job with the MERC 310 RX 7900 XT Black Edition, and it is worth considering if you have the money to spend. This card would excel at 1440p/144Hz and is very capable at 4K. Here at Overclocker’s, we have no qualms about giving it our seal of approval!

 

Overclocker Approval Rating
Click to find out what this means.

– Shawn Jennings (Johan45)

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JLK03F150

What have I done! Member

3,641 messages 644 likes

I'm glad to see the AMD 7900 XT/XTX cards being competitive with the RTX 4080 for less money (well, time will tell on that point :rolleyes:).

Thanks for the review, Johan.

Reply 2 Likes

EarthDog

Gulper Nozzle Co-Owner

74,620 messages 1,557 likes

Yep... even though the price difference isn't much between the 4080 and 7900XTX ($200). I think NV has to come down just a bit on this card.... which I'd guess will make them think about the cost of the 4070/4070Ti coming in early Jan (depending on where it's performing).

I'm really surprised about the power use. It uses notably more power than the 4080 all around, but especially with multi-monitor and idling.

We see nice gains in ray tracing but still behind NV (if that feature is important to you).

Reply 1 Like

JLK03F150

What have I done! Member

3,641 messages 644 likes

Even though RT has been implemented in MSFS2020, I'm not too concerned about it. It might make a difference in the Assetto Corsa series, but I'm just trying to not hit a wall or another car. I'm not looking at janky power lines overhead. lol

Yes, I'm hoping Nvidia lowers prices instead of AMD raising their prices to level the field.

Reply 2 Likes

Culbrelai

Member

1,803 messages 9 likes

What a terrible showing tbh. RT performance of these new AMDs is between 3080 and 3090ti. Worse power consumption than 4080, powerdraw bug with multimonitors (100w at idle oof), awful coil whine on reference designs, and super duper overpriced AIBs, to the point where the AIBs are reaching into 4080 price territory.

Looks like Vega Part II.

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Hardin

Member

3,373 messages 1 likes

They should have replaced the Xs with $s. Having said that though thank you for this review. It's a lot more favorable to the card then the other reviews I've been seeing. It looks like you might have to be very selective about which AIB you go with this generation.

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Johan45

Benching Team Leader Super Moderator

18,289 messages 163 likes

I'm really surprised about the power use. It uses notably more power than the 4080 all around, but especially with multi-monitor and idling.

Me too; a couple of things bother me about it. The first thing is in any DX12 bench, while overclocked, the fans will spin up out of control (3300 RPM). This is not temperature related, and the fans will stay at 100% until I exit the benchmark. I have seen this before and always felt it was driver/CCC related, something to do with their interaction. Second, the amount of power when overclocked seems way too high. So far, GPUz doesn't show GPU power draw, so I did some benches afterward with the Radeon overlay that does show many of these stats. The Radeon Overlay was showing 400 W plus for the total board use of the GPU. Technically that shouldn't be possible. PCIe 8-pin is 150 W x2 is 300 W + 75 W for the slot so a total of 375 W. At least, that's the way I understand it.

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EarthDog

Gulper Nozzle Co-Owner

74,620 messages 1,557 likes

Me too; a couple of things bother me about it. The first thing is in any DX12 bench, while overclocked, the fans will spin up out of control (3300 RPM). This is not temperature related, and the fans will stay at 100% until I exit the benchmark. I have seen this before and always felt it was driver/CCC related, something to do with their interaction. Second, the amount of power when overclocked seems way too high. So far, GPUz doesn't show GPU power draw, so I did some benches afterward with the Radeon overlay that does show many of these stats. The Radeon Overlay was showing 400 W plus for the total board use of the GPU. Technically that shouldn't be possible. PCIe 8-pin is 150 W x2 is 300 W + 75 W for the slot so a total of 375 W. At least, that's the way I understand it.

GPUz 2.51 was just released, maybe that has it?

Those numbers are the specs for the connectors. Most power supplies don't have anything stopping them from drawing at least a little bit more than that. Remember the 500W R9 295x2? That thing had the same config IIRC.

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Johan45

Benching Team Leader Super Moderator

18,289 messages 163 likes

GPUz 2.51 was just released, maybe that has it?

Those numbers are the specs for the connectors. Most power supplies don't have anything stopping them from drawing at least a little bit more than that. Remember the 500W R9 295x2? That thing had the same config IIRC.

Yes, but even according to the GPU specs it "shouldn't" be drawing that much power. With a +15% option, it still shouldn't be over 375W unless that's just a rough guide? Usually, we're fighting to get more power allotment.

That's the GPUz I used for the review

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Johan45

Benching Team Leader Super Moderator

18,289 messages 163 likes

any DX12 bench, while overclocked, the fans will spin up out of control (3300 RPM). This is not temperature related, and the fans will stay at 100% until I exit the benchmark. I have seen this before and always felt it was driver/CCC related, something to do with their interaction.

Ok, so I found this in the lit that XFX sent me:

Manually adjustments to the fan via the AMD Adrenalin Software will override the BIOS, a full driver wipe and DDU may be required to restore the factory BIOS fan profile any time a manual profile is used.

Since I do/will/did fiddle with the fan settings while overclocking, I followed this procedure, used DDU in safe mode, and reloaded the driver. Reran SOTR with the GPU overclocked, leaving the fans on auto, and had the exact same experience. The fans spun up and sat at 100% until I exited the game altogether. What's odd, though, is it's only while overclocked. If I reset the card to stock, it'll run fine, and the fans are barely audible.
I also tried switching from an Intel platform to a complete AMD platform, but there's no change.

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