Compute tests 2

AMD A8-3870K APU Review

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While APU’s (accelerated processing units) may not be as exciting as the top of the line speedsters put out by Intel, they do have their place in advancing processor technology. With the release of the first unlocked APU, the A8 3870K, AMD steps closer to making the APU a viable option for your every day computing and gaming needs.

APU: CPU and GPU in one package

APU: CPU and GPU in one package

Features and Specifications

APU’s are aimed to be low power-consumption CPU’s with better than integrated video GPU’s. They’re also supposed to be light on the wallet. So, they are meant for multimedia decoding and light 3D acceleration; think HTPC, media server, or basic desktop system.

Model A8-3870K
Radeon™ Brand HD 6550D
CPU Clock Speed 3.0GHz
CPU Cores on Die 4 cores
TDP 100W
Total L2 Cache 4MB
Radeon™ Cores on Die 400
GPU Clock Speed 600 MHz
DIRECTX® Version 11
UVD UVD3
DDR3 Speed 1866

the A8-3870K

the A8-3870K

Pin shot

Pin shot

905 pin FM1 socket compatibility

905 pin FM1 socket compatibility

Overclocking

The stock reference clock on the A series “Lynx” platform is 100 mHz. This reference clock sets the base frequency for the CPU, GPU, memory, North Bridge, SATA, and USB. Because all these subsystems are effected, overclocking via reference clock can sometimes be very tricky. Black Edition or unlocked processors allow you to change the multipliers while leaving the reference clock alone, putting less strain on the overall system, and thus are more desirable for overclockers like us.

AMD sent over a fairly in-depth overclocking guide with the A8 3870K that was filled with nifty tips and tricks to push this processor to it’s fullest. The main things in that guide that were slightly different than overclocking a normal processor were:

  • Use an HDMI or DVI monitor when overclocking the GPU
  • Leave the CPU at stock, or possibly underclock the CPU, to get the most out of the GPU. The reverse is also true if you want more CPU performance. This makes sense because the CPU and GPU are on the same chip and creating heat together. Decreasing one leaves more room for the other.
  • “NCLK (north bridge clock) has a notable effect on overall system performance.” I didn’t specifically test this statement, but you will see it roughly increase 1:1 with memory clocks.
  • To get higher reference clocks, change the SATA mode to IDE. AHCI mode is stated to limit the clock speed to about 5% over stock, or roughly cap at 105 MHz. IDE mode should allow for 33% increase, or a running clock of 133 MHz.

In the same document, AMD also stated some targets for overclocking. So, I had a pretty good idea what I was aiming for when I finally got the chip installed and turned on.

GPU clock => 800 – 960MHz (@ 1.20….1.30V)
NB clock => 900-1100MHz (@ 1.20…1.30V)
CPU clock => 3500-3800MHz
Memory clock => 933-1200MHz (depending on DIMM spec)
ref. clock => up to 105MHz (in AHCI mode) / up to 150MHz (in IDE mode)

In my own testing, I found the values listed above to be very accurate. The highest CPU clock I was able to achieve was 3850 MHz (35×110 MHz, 28% increase) but I had to drop down to 3720 MHz (31×120 MHz, 24% increase) to complete benchmarks while on air cooling.  For the GPU, I could only hit 864 MHz (44% increase).  My maximum base clock was 160 MHz and I was able to push my RAM to 1080 MHz (800 MHz stock, 35% increase).

Maximum BCLCK achieved

Maximum BCLCK achieved

Maximum CPU clock achieved

Maximum CPU clock achieved

Maximum RAM clock achieved

Maximum RAM clock achieved

Benchmarks

For the different tests, I compared the A8 3870K against other systems I have tested in the past. Unfortunately, the number of tests we run has changed over time and I didn’t have time to go back and rerun them on the older hardware, so some of the systems are missing some of the tests (represented as 0.00 in the graphs below).

Hardware Line Up

AMD A8-3870K Zotac Fusion ITX A Series Mvix Minix 890GX-USB3 Mvix Minix 6150SE-UC3
Processor AMD A8-3870K AMD E-350 APU (integrated) AMD Phenom II 560 BE AMD Phenom II 560 BE
Motherboard Gigabyte GA-A75M-UD2H Zotac Fusion A Mvix Minix 890GX-USB3 Mvix Minix 6150se-UC3
RAM G.Skill RipjawsX 2x2GB DDR3-1600 Kingston 2x1GB DDR3-1066 ADATA Supreme 2x2GB DDR3-1333 ADATA Supreme 2x2GB DDR3-1333
Graphics Radeon HD 6550D (integrated) Radeon HD 6310 (integrated) Radeon HD 4290 (integrated) NVIDIA GeForce 6150SE (integrated)

Tests

The main thing to take away from these compute tests is that the A8-3870K running at stock 3.0 GHz actually performs like a normal dual core Phenom II processor, even beating the 3.3 GHz 560 BE in a few tests. This might not be amazing to some of you, but for others, like me, this is very nice to see.  Personally, I was expecting performance to be more on-line with the E series processors (like the E-350 in the Zotac Fusion A board). Of course, the different RAM speeds might have played a small part in the A8-3870K doing better, but I think it’s safe to assume that wouldn’t have caused the large marins in the 2nd graph.

Compute Tests

Compute Tests

Compute tests 2

Compute tests 2

For the gaming and graphics tests, I added the Biostar Nvidia Geforce GT240 and AMD Radeon HD 5550 to the mix. These are two other low power HTPC cards I tested in the past. Unfortunately, like the graphs above, I didn’t have data from all of our current tests. But, I still wanted to show how they compared in the tests I did have data for. So, I apologize in advance if the graphs are little ugly with all the missing data, but hopefully they are still informative.

What I like about these graphs is that they show the new A8-3870K blows away any other current integrated graphics offering. This doesn’t mean that you can play the newest games at full settings and full resolution, but it does mean that newer GUIs that are 3D accelerated will be smoother and video rendering will be better. So, these A8 processors will work well as a cheap desktop, workstation, or HTPC but you should still add in a discrete GPU if you want to play games.

Gaming tests

Gaming tests

Synthetic Gaming Tests

Synthetic Gaming Tests

Conclusion

Overall, the AMD A8-3870K APU did very well and exceeded my expectations. It performed very well when compared against other integrated graphics solutions and even when compared against other low-cost processors. Most importantly; it overclocks fairly easily! So, us hobbyists who like to stretch our wallet and tweak our hardware will have a great time with this chip. Sure, it’s no hotrod, but for the price ($119.99 at Newegg right now) you get decent computation capabilities and graphics capabilities in one little package. Mainly for the better-than-average 3D performance, I’m marking this processor Overclockers Approved.

Thanks, AMD, for sending this processor over for testing.

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Discussion
  1. You'd be suprised how well they perform for most stuff, I was more than comfortable playing world of warcraft on one in a raid. It was overclocked a decent amount but it was extremely smooth and no fps problems at all.

    Plus 3870k's are great overclockers while cold if your interested in ever going that route.
    i actually got selected to review one of these. amd is sending me one for free. i really dont think im going to build a system for this. might sell it for more parts for water cooling

    i like the idea of putting 2 in one. but dont think its for me
    That's their generational architecture name..lol. we are talking public name.
    ssjwizard
    Ahh a year later and people are still fighting about who owns the K tag for there chips... Clearly AMD put the K on the back on of the APU to try and look like the Intel 2500/2600k series chips. However, as most of us here already know AMD has been using the K nomenclature longer than Intel has(k6, k6-2,k7,k8,k10,etc). The 3870k is a fun little chip my wife is enjoying hers @ 3.6Ghz in dual graphics /w 6670 since last fall. Good stuff!
    Very late in the day if you don't mind me saying :) they are about to be taken over by Trinity, all thought this is useful to new adopters of APU's i guess, as they will get pretty cheap before long to clear space for Trinity.

    Are we going to see some Trinity tests here any time soon?
    I have caught myself doing the same thing a few times when people posted stuff in general spots about the socket 2011 cores. The Angry geek in me goes into a rage, then I read it again and realize I am the slow party. DOH :(

    Good review man :D
    Ok. I get you know.

    I got confused by ssj's post. 3870k and 6670 dual graphics. Then I realized what review I was reading..:bang head

    This is gonna confuse our average Joes.
    Ahh a year later and people are still fighting about who owns the K tag for there chips... Clearly AMD put the K on the back on of the APU to try and look like the Intel 2500/2600k series chips. However, as most of us here already know AMD has been using the K nomenclature longer than Intel has(k6, k6-2,k7,k8,k10,etc). The 3870k is a fun little chip my wife is enjoying hers @ 3.6Ghz in dual graphics /w 6670 since last fall. Good stuff!
    The folks we deal with are outsourced marketing and likely didn't have anything to do with the naming. I won't bother them to dig back at HQ about this one; but it definitely is amusing they went with K when it's very hard not to notice Intel K- CPUs have been around for a while. :shrug:
    rescuetoaster, I think he's referring to the "K" part. I agree it's pretty silly. Black Edition, or just BE would be more in-line with AMD's naming conventions.
    I.M.O.G.
    Any comment from AMD on how they chose the naming convention? Seems confusing when AMD has a 3870K and Intel has a 3770K in their current product lineup.


    Well the A8 3850 was released last summer, so technically they laid claim to that chain of names a while ago.
    I.M.O.G.
    Any comment from AMD on how they chose the naming convention? Seems confusing when AMD has a 3870K and Intel has a 3770K in their current product lineup.


    duh everyone knows the 3870k is faster than the 3770k :rofl:
    Any comment from AMD on how they chose the naming convention? Seems confusing when AMD has a 3870K and Intel has a 3770K in their current product lineup.