Sapphire 7970 - Overclocking

[Renegade40D]

Ok so i got a 7970 with an EK full waterblock, added it to my loop, runs well, plays bf3 well. And of course despite that i thought hey lets see what it gets in 3D Mark 11 and then OC it and try again.

System is : i7 950 (stock) / Sapphire 7970 / 12gb ram / intel 520 ssd / MSI X58 Pro Sli

Just using the overdrive feature in CCC my first OC i went to 1075/1475, ran 3dmark no problems, score went up. Upped the oc the full 200 for each to 1175 /1575 and it had artifacts during 3dmark, dropped it by 50 on each and it still had artifacts throughout the tests. I thought maybe it was just luck of the draw and that the chips just aren't good overclockers.

Someone in the 3Dmark11 thread suggested maybe i have a 1.05v card, not the 1.125v card. So i downloaded MSI afterburner and with all default values the card read VDDC of 1.17v. So that got me doing some googling and lead me to look up the ASIC readout which is 82.4%

So now the more i try and look into this the more confused i get.

Some people say get a better PSU (relating to low ASIC scores).

And the other thing i noticed is that the card is PCIe 3.0 capable but my mobo is only PCIe 2.0, not sure if that would make a difference.


So basically interested in OC'ing my whole machine and doing a few benchmarks for the hell of it, and the starting point was the new GPU, which im guessing is not a very good overclocker or is there things i can do like bios updates for gpu / mobo that would make a difference?

[D_W_Y]

i am not even sure if these cards max out the bandwidth of 16x pci2.0? people seem to be happily running them in xfire* on pcie2.0. bit like sata3 hard drives, just cus.

[RB Snake]

1175Mhz is going to far without upping the voltage. even maxing the ccc (catalyst control centre) limits of 1125Mhz is not possible with all 7970s. But with most it's possible. You've got a fairly high asic% for a 7970 that means you default voltage is usually lower that than rest. Could be why it's unstable even at max ccc limits. Use GPU-Z or Sapphire TriXX to check what the default voltage is.

When I had a sapphire 7970 it's default voltage was 1050mV. It could not reach 1125Mhz, it was to unstable. I increased the voltage to 1125mV and it was perfectly stable. MSI afterburner would also thing that my card was running at 1175mV when it was not.

Like I said in the 3dmark11 thread most of the 7970s default voltage is 1175mV there the ones that oc easily to the ccc overdrive limits of 1125Mhz/1575 etc...

[ShadowBurger]

you won't max out pcie 2.0, did some research as I just ordered one and not even the GTX690 will