Radeon HD 5970 -- the overclocking experience

Last Wednesday when the Radeon HD 5970 launched, the product was extremely well received by the hardware enthusiast community. And for valid reasons as it is an incredible piece of hardware. As we stated in our article -- the product is clocked a little conservative though. AMD needs (wants) this graphics card to run under a peak wattage of 300 Watt. Clocking the product any higher they would have broken that limit, likely set by PCI-SIG which decided upon a 300W GPU limit for graphics cards.

ATI literally enforced a hardware limitation by implementing a 6-pin and 8-pin power header on the card. Meaning, 75W is delivered through the PCIe bus - 75W on the 6-pin header and 150W on the 8-pin header. That's in total 300W available for the graphics card.

Now with a TDP of already 294W you'd think that there is no overclocking (6W) headroom left. Well, if you have a proper power supply with some more Amps on the 12 rails or have a PSU like PC Power and Cooling offers (ditch all available AMPs on one big fricking 12V line) then you can imagine that we can easily pass that 300W limitation and take the R5970 to sat ... 400W.

So let's try that out. Now for a successful (massive) overclock you'll be needing a little extra voltage on the GPU though. So today we are going to overclock the Radeon HD 5970 and break away from that 300W limitation. This is why we ALWAYS say, get yourself proper equipment .. and in the case of a PSU, some reserves.

Our end result ? We boosted the Radeon HD 5970 Core from 725 MHz towards 935 MHz and the 4000 MHz memory is running and purring steady at 5240 MHz completely stable ---  and that's a baffling result on just the reference air-cooler.

Wanna learn how we do it ? Well read the next couple of pages, and sure benchmark results based on our overclock experience are included as well.

Next page please ...