Date:
Wednesday, November 18, 2009
Author:
Brent Justice
Editor:
Kyle Bennett
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AMD ATI Radeon HD 5970 Video Card Review

Just when you thought there was no way to outdo the 5800 series, AMD gives us the ATI Radeon HD 5970. It has two GPUs on a single PCB and brings with it CrossFireX in a single PCIe x16 slot. We show you if it is worth your hard earned cash.

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Overclocking

Note: These overclocking results may not represent the abilities of retail video cards since these are engineering samples. We figure if 5970 GPUs are cherry picked; our samples might "really" be cherry picked. :O

We utilized Overdrive in Catalyst Control Center to overclock the ATI Radeon HD 5970. Overdrive now allows up to 1GHz frequencies for GPU and 6GHz for memory with the Radeon HD 5970. We also obtained an over-voltage program from AMD to allow us to over-volt this video card and see how high we could increase GPU and memory frequencies.

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The stock frequencies of the Radeon HD 5970 are 725MHz GPU and 4GHz GDDR5 memory. The stock voltages are 1.05v vCore and 1.10v for the memory.

Without performing any modifications, just using Overdrive to overclock, we weren’t able to take the two GPUs as far as we guessed. We managed to hit 800MHz stable, just 50MHz shy of Radeon HD 5870 clock speeds. Keep in mind that we are overclocking both GPUs at the same time, so you are only as strong as your weakest link. We managed to overclock the memory quite well though, up to 5.2GHz, surpassing the memory frequency on the Radeon HD 5870 easily.

The real fun began when we applied over-voltage to the GPU and memory. Taking the GPU from 1.05v to 1.1625v resulted in an increase of 100MHz on the GPU! We were able to have a stable experience at 900MHz GPU frequency. In fact, we were even able to play a few games at 925MHz just fine. The Left 4 Dead 2 Demo ran just fine with the GPU at 925MHz. We also managed to play Borderlands just fine at 925MHz. However, Crysis crashed on us rather quickly. So the more graphically intense your game is, the more sensitive it will be to clock speed increases. Overall, 900MHz netted a stable experience in every game for us.

Taking the memory from 1.10v to 1.15v resulted in a smaller increase up to 5.4GHz GDDR4 compared to 5.2GHz GDDR5 before. This is a small bump, but still a very respectable clock speed overall. When all is said and done, our final overclocks were 900MHz/5.4GHz.

Power Testing

We tested the power utilization at the wall of the entire system without a video card, and with each video card at idle and full load. For full load power and temperature testing we used FurMark version 1.7.0 to stress each video card at the highest load. We found 2560x1600 to be the sweet spot for stressing the GPUs without bottlenecking them. The power supply used in testing is a PC Power & Cooling Turbo-Cool 1200W. Our system is very lean with only one optical drive and one hard drive being powered. Total system wattage at idle without video card is 165W.

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Do not be alarmed at the full load wattage results here. What we found out is that Furmark really pushes the cards, harder than any game will. In all the games we tested we never saw full load system wattages of these magnitudes. With the ATI Radeon HD 5970 we experienced an average of 425 Watts full load when we were playing games, this includes Crysis, Borderlands and Batman. Taking the card to its limits you can see Furmark pulled out 520 Watts from the wall. The idle Wattage was 216 Watts, just a few Watts higher than Radeon HD 5850 CrossFireX for some reason. Take into account PSU efficiency of 82% or so, and our 12v power usage comes in at around a peak of ~425 watts (520*.82). So a well built 620 watt PSU would be right at home on our system. In the real world when you start adding hard drives and all sorts of cooling to your systems you would likely be better off with a 750w PSU if you are the benchmarking and stability type.

With the ATI Radeon HD 5850 CrossFireX configuration installed we noticed higher Wattage while playing our games compared to the Radeon HD 5970. Furmark pulled 548 Watts from the wall, but in gaming we saw on average around 450 Watts.

With the GeForce GTX 295 we noticed full load Wattage was lower compared to the HD 5970 and 5850 CrossFireX. Considering both are much faster than the GeForce GTX 295 this makes sense. Idle Wattage was much better with the new HD 5970 and HD 5850 CrossFireX compared to the GTX 295.

The Radeon HD 5870 had the lowest idle Wattage of all, as well as the lowest full load Wattage, since it is a single-GPU video card.

Overall it appears that the Radeon HD 5970 is more power efficient at full load compared to Radeon HD 5850 CrossFireX.

Temperature Testing

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When we looked at the idle temperatures on the Radeon HD 5970 we had expected to find one GPU very warm and the other much cooler. However, Overdrive showed us that one GPU was at 44c and the other GPU was at 0c. Therefore, it seems that while asleep, Overdrive is having trouble telling us what the actual temperature is of the second GPU is and is resulting in a broken value. We need a third party utility that can utilize the monitoring hardware on board to better test what the idle temps of both GPUs are, or this one simply needs to be fixed. With the ATI Radeon HD 5970 we found idle GPU temp on one GPU to be 44c. At full load both GPUs rose to 87c in Furmark. Overclocking at the "No Modification" setting yielded just a 1c increase in temps. This seems to reflect the fact that the new heatsink/fan unit is certainly doing what it is supposed to.

We also experienced Overdrive showing us 0c on one GPU for the ATI Radeon HD 5850 CrossFireX as well, so it seems the utility cannot read the second GPU correctly at idle. The idle GPU temperature on one of the cards was higher than one GPU on the ATI Radeon HD 5970. At full load HD 5850 CrossFireX reached a higher 88c on both GPUs. It seems ATI Radeon HD 5970 is also more efficient at cooling as has been suggested to us by AMD.

The GeForce GTX 295 is just a monster at both idle and full load.

The ATI Radeon HD 5970 was 4 degrees warmer at idle than the Radeon HD 5870. At full load though the 5970 was actually 1 degree cooler than the 5850CFX.

Fan Noise

At idle, just sitting in Windows, the ATI Radeon HD 5970 is quiet. When we were playing games we noticed the fan spun up, and wind noise increased, but our system is sitting right next to us at shoulder level when we game. If this were in a case I’d imagine while gaming it would be difficult to hear. However, when we ran Furmark and Overclocked the video card, the fan spun up very high, and the wind noise was very apparent. The video card is most certainly not quiet when Overclocked or when the fan ramps up to full speed. We also noticed it does blow a lot of hot air, with great force, out the back when raising the voltage and overclocking and running Furmark at full load. If you are going to be raising the voltage and clock speeds we recommend having some extreme cooling in your PC as well as clearance behind the case.