Despite its name, the PowerColor HD 6950 PCS++ is not an average reference card. This GPU is built on a custom PCB and includes a different cooling solution than reference cards. Out of the box, this card is unlocked from 1408 shaders to 1536 shaders, like the HD 6970. Plus, it comes standard with a beefy 80 MHz overclock. Basically, this is an HD 6970 with slower memory speed.
Specifications and Features
|Graphics Engine||RADEON HD6950|
|Video Memory||2GB GDDR5|
|Engine Clock||880 MHz / 800 MHz|
|Memory Clock||1250 MHz|
|Bus Standard||PCIE 2.1|
|Standard Display Connectors||DL-DVI/SL-DVI/HDMI/2* mini DisplayPort|
|Minimum System Power Requirement||550W|
|Extension Power Connector||1 6-Pin and 1 8-Pin PCI Express Power Connectors|
This card comes standard with all the bells and whistles of the reference version of the HD 6950, including eyefinity support and improved tessellation. The difference here is in the dual-BIOS setup, default is 880 MHz core, 1250 MHz memory and 1536 shaders (same core speed and shader count as an HD 6970). The back-up BIOS features 800/1250 and 1408 shaders (same as the reference HD 6950).
Unlocking the extra shaders via a BIOS update took five minutes and was extremely simple. This is even easier, just a flick a switch from position 1 to position 2. This is definitely going to be appealing to some of those hardcore gamers who lack the interest in overclocking their hardware. I would have preferred if BIOS 2 was enabled by default, but it’s so simple that it really is not a major drawback, even for the most novice user. PowerColor refers to BIOS 2 as “Main BIOS,” so I will refer to stock configuration from here forward and use it for my performance tests.
One of the other main differences between reference cards and the PowerColor PCS++ version is the cooling system (see picture below). This is a complete reversal from the reference 6900 series cards, like the 6970 we reviewed, which features “a standard squirrel-cage intake that exhausts out the rear of the case, but it uses a vapor chamber rather than a heatpipe design.” It looks as though both versions of the card have a copper base and aluminum fins. The difference is the PowerColor card has three 8mm heatpipes and two 92mm fans. The marketing material below claims the fans allow for 60% more airflow than a normal 80mm fan. While those numbers may not be entirely accurate, it is pretty clear two full-size 92mm fans can out-muscle the smaller exhaust fan on the reference cards. Don’t get me wrong, AMD’s vapor-chamber design is a step-up in video card cooling, but it seems like PowerColor really stepped up their game.
|Card:||Sapphire HD 6950||PowerColor HD 6950 PCS++|
|Overclock/Settings:||Flashed – 880/1375||880/1250|
|Idle||33° C||33° C|
|Load – 50% Fan Speed||51° C||71° C|
|Load – 100% Fan Speed||57° C||69° C|
This is one of those situations where the numbers do not tell the whole story. In looking at the above chart, it seems like the PowerColor card has a bit of wiggle room for voltage increases and a heavy dose of overclocking. These temperatures were recorded only after I re-applied TIM, which shaved 10-15° C off the original temperatures. This may have been due to poor factory application of TIM or the heatsink becoming unseated during shipping. The results were quite surprising, I was almost certain the custom heatsink would put the reference cooler to shame. It is possible that the PowerColor card has some additional stock voltage since it does come with a modified BIOS, although I was not able to confirm that. The PowerColor cooling solution does have one distinct advantage, it is much quieter than the reference card.
The photos below depict the cooling solution in detail. Three copper-colored heatpipes converge in the center into a copper square. The rest of the cooler features aluminum fins. In the bottom of the first photo (although it would be on the top of the heatsink, technically) is a small green strip of thermal tape, which makes contact with the four ram chips above the GPU-core. The four ram chips to the side of the GPU-core do not make direct contact with the heatsink, but frequently the airflow from the fan is sufficient enough to cool them down.
The PowerColor HD 6950 PCS++ comes with the standard accessories: a DVI adapter, CrossFire bridge, driver CD and manual (not pictured). Also included is a Mini-Display port to DisplayPort adapter and redemption code for the full version of Call of Duty: Modern Warfare 2. This is a great bonus since the game retails for $25.99 on Newegg.
|Sapphire HD 6950 (reference card)||$256.99|
|PowerColor PCS++ HD 6950||$289.99 (MSRP)|
|Lowest pricing per model at Newegg.com as of March 1, 2011|
This card fits nicely between the GTX 470 and 570, the same gaping performance/price hole seen at the time of the HD 6950’s launch a few months back. Even though this card will have a $30 premium over the lowest priced HD 6950 on the market, it comes unlocked right out of the box. I expect the price to drop a bit over the next few weeks, so it won’t be $30 more for long as rumors of HD 6900-series price drops have surfaced across the board. With the price tag, the custom PCB and cooler as well as the overclocking results will factor in heavily when evaluating this card. Is it a good value compared to the competition? Short answer is “yes,” NVIDIA does not have anything in this price range and the HD 6970 is over $80 more expensive. The main aim will be proving the extra $20-$30 for this card is worth it, since it is already established that the HD 6950 reference card is a good value.
Test Setup and Methodology
|Processor||Intel i5 655k @ 4.85 GHz|
|RAM||Kingston HyperX DDR3-2000 4GB|
|Video||AMD HD 6950|
|Power Supply||Corsair 650w|
|Operating Systems||Windows 7 x64|
All benchmarks were run three times using the “performance” preset and the average result is displayed. The 3DMark scores presented are run using the Performance (‘P’) preset.
Important Note: None of the graph abscissa ranges begin at zero. This was necessary to be able to display the differences in the scores, which are typically very high numbers all round. The actual scores are printed on each graph.
The first step is disabling the PowerTune technology which automatically adjust the voltages based on the GPU load. It’s simple, just set “+20%” on the voltage control slider in Catalyst Control Center (CCC). Next crank the clocks to get the highest possible score for both the core and memory. My preferred strategy is to isolate the core first, then the memory, and use the maximum attained scores. At the end, I did have to make some adjustments to the maximum clocks I achieved. After some stability testing, here are the maximum clocks:
A 925 MHz core clock was not overly impressive, but the 1550 MHz memory speed was higher than I expected. Both clocks shattered the maximum memory clock I achieved on the AMD HD 6950 sample (1425) by almost 9% and barely beat out the Sapphire HD 6950 (1515), also a reference card, to be reviewed later. The core speed is respectable, but could be pushed a lot further given a voltage adjustment. This option is now available in the newest version of Sapphire TRIXX, but was not explored in this review to keep the playing field level.
Not a bad showing here from the PowerColor card , which outperformed the Sapphire HD 6950 by 8% at stock speeds and nearly 13% at maximum overclock (925/1550).
Similar results here with the newest version of 3dmark, the PowerColor PCS++ at stock performed 5% better than the Sapphire card and 11% better at it’s maximum overclock (925/1550).
In looking at both the above graphs, there are some unified conclusions that can be seen. The Sapphire HD 6950 is however capable of similar scores to the PowerColor PCS++, but not right out of the box, so the edge here has to go to the PowerColor card. At a 13% price premium over the Sapphire model, the performance does not exactly match up with the price-point, however the added accessories more than make up for the difference. Plus, I still expect the price to fall in the near future and 1550 ram speed is very high compared to the competition.
Heaven is a benchmark that really puts the GPU to the test. In stock configuration, the PowerColor PCS++ beats the Sapphire card by 11%. The PowerColor PCS+ at stock (880/1250) even edges out the Sapphire card flashed to 6970 BIOS running at 880/1375. The numbers are quite close, but it is still worth noting. With the maximum overclock, the PowerColor card has a 14% edge on the stock Sapphire card.
Aliens vs. Predator is a great benchmark to test how a graphics card can handle the latest gaming engines under DirectX11. Similar to the Heaven test results, the PowerColor PCS++ beats the Sapphire card at stock by nearly 11%. The maximum overclocks of both cards are just about even, but note the Sapphire card handled a higher GPU overclock, while the PowerColor memory was much stronger.
The same methods for comparing performance were used in this review as my initial HD 6950 article:
Without a slew of video cards to compare in the same machine, we came up with a different solution for comparing relative performance. This solution is not without its flaws, but it should give a relatively clear picture. My system score (or CPU/Physics score) trended on the low side, so this analysis will include my average system/CPU score from both 3DMark Vantage and 3DMark06. Using a static system score, I was able to sub in the varying GPU scores into the score calculation equations provided by Futuremark.
GPU scores were generated by taking an average of the top 5 scores of each of the respective video cards on HWBot that met the following parameters:
- Cooling: Stock or Air
- Cores/# of Cards: 1
- i5 CPU
- Cooling: Water or Air
This type of testing gives the clear advantage to HWBot scores for several reasons:
- These are the Top 5 scores that meet the above parameters, not just typical user scores. Many of these scores were achieved by some of the top overclockers on HWBot.
- On average my CPU score was significantly less than the HWBot scores. Though I removed the CPU scores from the results, the overall system still does impact final scoring.
- Scores on HWBot may or may not have had the advantage of custom BIOS or increased voltages, while the HD 6950 voltage is locked.
Right out of the box and at stock speeds, the PowerColor 6950 PCS++ beats the GTX 470 by 7% and the GTX 460 by 14%. Keep in mind, these scores were taken from some of the higher results on HWBot, so I consider this a win for the PowerColor card. When taking my top overclock and comparing to the best results on the bot, the PowerColor card edges the GTX 470 by nearly 12%. The PowerColor PCS++ card is priced substantially higher than most GTX 470s, so these results are to be expected. Let’s see how it stacks up against the higher-priced GTX 570, which starts at $334.99.
Like in my last review of the reference card HD 6950, there were not enough GTX 570 submissions on hwbot.org to support the above guidelines. Like before, I am eliminating the CPU restrictions in order to do a rough comparison of the PowerColor HD 6950 PCS++ and GTX 570. Using the same Vantage score as in my previous review 20922 (which was the average of thirteen results based on my guidelines, minus the CPU restrictions). This score marks nearly a 7% increase over my top PowerColor scores. Considering that the GTX 570 costs 13% more than the MSRP of the PowerColor PCS++, this is a reasonable difference between the two cards. It makes the PowerColor card a great value, despite it being $30 more than the reference version 6950s on the market.
|Card||Vantage Score||Price||Vantage Pts. per $|
|HD 6950 PCS++||19513||$289.99||67|
From a value perspective, it is difficult to ignore the above numbers. Neither option is a poor choice, but the PowerColor card does provide better value per dollar than the GTX 570.
Pretty simple you get a 6970 out of the box for barely above the price of a 6950. There is no guarantee that ram will achieve stock 6970 speeds, but it’s pretty likely. In fact, the memory on this card overclocked by a minimum of 35 MHz more than the other two HD 6950s that I have tested. The cooling performance was definitely not what I was hoping for, but with some TIM re-application and some extreme fan speeds, there is plenty of potential here. Despite the rather hefty $30 price premium, this card retains a strong value proposition like the reference versions of the HD 6950.
– Matt Ring (mdcomp)