ATI - Radeon HD 5970 review
two ATi HD 5870 chips on one card
Review date: 23 December, 2009. Review by: IT Reviews Staff
The HD 5870 supports DirectX 11, OpenGL 3.2 and Shader Model 5.0 and uses a 40nm fabrication process that has allowed ATi to pack in double the number of Unified Shaders we saw in HD 4000. The mighty HD 4890 had 800 Shaders but this was trumped by HD 5870 with 1,600 Shaders. There are two chips on the new graphics card so that's a total of 3,200 Shaders plus 2GB of GDDR5 memory.
The two chips are linked by an ATi PCI Express 2.1 bridge chip to join them in permanent CrossFireX.
That's an awful lot of hardware to accommodate on a single graphics card and it is our opinion that ATi has done well to only extend the board from 280mm for the HD 5870 to 310mm for this HD 5970. You'll need to check that your case can accommodate such a lengthy graphics card as the location of the drive bays and motherboard connections may well pose a problem.
An HD 5870 has a maximum power draw figure of 188W so we can estimate that the ‘natural' power draw of HD 5970 would be higher than 350W, which is an astronomical figure for a graphics card. ATi tells us that the cooling package on HD 5970 can handle 400W so this would seem to be possible, but we assume this would require the cooling fan running at full speed and that would be horribly noisy.
As a compromise ATi has reduced the operating voltage of the chips and memory in HD 5970 and has also reduced the clock speeds from the 850MHz/4800MHz figures we saw with HD 5870 to the 725MHz/4000MHz speeds that are familiar from HD 5850. The result of this fettling is a maximum power draw figure of 294W for HD 5970, but that's not the end of the matter.
The display outputs on the double-slot bracket have been changed from the arrangement used on HD 5750, 5770, 5850 and 5870 where the dual DVI outputs were stacked on top of each other with an HDMI and DisplayPort alongside. The modified layout for HD 5970 has two dual-link DVI outputs and a mini Display Port arranged in a row across the lower level of the bracket which leaves the upper level free to work as an exhaust vent for the cooling package.
You can expect that every HD 5970 will include an adapter to convert the mini DisplayPort to a regular DisplayPort along with a DVI-to-VGA adapter, a DVI-to-HDMI adapter and power adapters for both six-pin and eight-pin connectors. You'll probably also get a voucher for Dirt 2 on Steam.
Testing the HD 5970 on a Core i7 PC was an awesome experience and the sample cards we had from HIS and Sapphire both delivered more than 20,000 marks in 3D Mark Vantage. That's 20,462 for the HIS and 20,666 for the Sapphire which reflects the fact that the HIS is clocked at 725MHz/4000MHz while the Sapphire runs a shade faster at 735MHz/4040MHz. Using Full HD settings we saw frame rates in Battle Forge around 85fps while Far Cry 2 raced along at more than 130fps.
Connecting the two HD 5970 cards in CrossFireX raised the 3D Mark Vantage score to 29,745 marks and lifted the Battle Forge frame rate to 125fps. The Far Cry 2 frame rate only increased slightly to 146fps which suggests that you need a screen resolution higher than Full HD to stretch a pair of HD 5970s in some modern games.
Overclocking the HD 5970 threw up an interesting problem as the reduced voltage settings that have been stipulated by ATi make the task almost impossible. We were able to overclock the HIS from 725MHz/4000MHz to 790MHz/4400MHz which is an improvement of ten percent, however those clock speeds are considerably lower than the 850MHz/4800MHz speeds of HD 5870.
Included with the Sapphire HD 5970 is a copy of its Redline utility which allows you to adjust the core voltage from 1.105V to 1.1625V and to raise the memory voltage from 1.1V to 1.15V. That might not sound like much extra power but the result is that the Sapphire overclocks to 890MHz/4600MHz which resulted in a 3DMark Vantage score of 22,593 marks. This extra clock speed raised the loaded power figure by 90W over and above the stock HD 5970, which is a significant amount and shows us why ATi set the voltages and clock speeds so low in the first place.
Verdict
HD 5970 is a big, long graphics card that draws a hefty amount of power and chucks out a significant amount of heat when it is working hard. The 40nm fabrication process has allowed ATi to cram in a massive number of Unified Shaders and the result is that HD 5970 delivers a colossal level of DirectX 11 gaming performance. On the downside the price is equally colossal but when it comes to hardcore gaming we feel that HD 5970 is the only show in town.
Company: ATI
Contact: 00 1 408 749 4000
