ATI 5000 Series Roundup
Published: 20th January 2010 | Source: ASUS | Price: £117 - £540 |
Test Setup and Overclocking
Naturally testing something as potentially insanely powerful as the 5970 requires all the beef it's possible to get to push the cards as hard as we can. Although it would be possible to go really mad and get the LN2 out, we always feel that the results we obtain at OC3D should be easily replicated in the real world by our readers and so we've stuck to a sensible overclock that should be enough.
CPU : i7 965 overclocked to 3.6GHz
RAM : 6GB of OCZ Blade
Audio : ASUS Xonar Audio
Motherboard : ASUS Rampage II Extreme
PSU : 1000w OCZ Gold
GPU : ASUS HD5970, HD5870 and HD5870xf, HD5850 and HD5850xf, HD5770
OS : Windows 7 Ultimate 64
Drivers : Catalyst 9.12
Many early reports about the 5850 said that it could achieve much higher clockspeeds than those they ship with by default, and that the 5970 voltage and speeds were intentionally kept low by ATI to keep the card under the 300w threshold. As the ASUS cards make it so easy to adjust the voltage and push for those high GPU clocks it had to be done.
Firstly please note that the only overclocks were done to the GPU clock as the GDDR5 clock speeds are already pushed high at stock and any overclocking to the memory produced negligible increases, so we concentrated solely upon pushing for the best GPU overclock we could obtain. Stability was determined by a two hour gaming session with the details maxed out. As long as there were no artifacts observed then we considered the overclock to be stable.
Starting with the ASUS HD5770 which actually ships with the highest default voltage of any of the cards on test today we managed to increase the core speed from 850MHz up to 950MHz by upping the voltage from 1.124v to 1.25v.
The HD5850 is the card we were most interested in as it had the potential to produce the biggest gains, and sure enough the default clock speed of 725MHz was managed to be increased to a mind-bending 1GHz core with voltage upped to from 1.15v to 1.275v. A staggering increase.
The ASUS HD5870 ships with 850MHz core and as this is the highest performance single card available we weren't expecting a large increase yet once again the ASUS voltage mod BIOS enabled us to reach 950MHz on the core with the voltage increased from 1.15v to 1.225v.
Finally the HD5970. When ATI first announced this card they took pains to point out that the clock speeds have been kept low to stay within the specifications demanded of a PCIx slot. However as we don't need to stay within an arbitrary limit the default 725MHz at a very low 1.049v swiftly became 900MHz at 1.275v. A very handy increase although we're really stretching the abilities of the 5970 thermal solution.
Remember that we ensured that all the cards were stable over a long period of gaming before declaring it successful overclocks and therefore we didn't think we'd see the egg-frying temperatures some of the early DirectX 10 cards experienced and sure enough we didn't.
The main things to take from this graph are :
1) For all the single chip cards they have lots of headroom for overclocking. Whilst 70c is quite high, it's only similar to the stock results of the last generation, proving the evolution of the cooling solution employed.
2) The 5850 clearly has insane amounts of headroom. To get a 33% increase in clockspeed for only a 5c increase in temperatures is nothing short of outstanding.
3) Finally, it's clear that although the 5970 is perhaps conservatively volted and clocked, it clearly is right at the limit of how much heat the fan and heatsink can expel. We really pushed it to its limits for our testing and it was loud, but it was stable. We'd definitely suggest accepting the extra noise that 100% fan speed brings to get those temperatures down if you plan on running a 5970 full-time.
I hope you're all sitting comfortably, because there is a wealth of data and graphs upcoming. So get your comfy chair and a brew and settle in.