XFX 7970 OC Help plz

[MikeGT2]

Hi,

I have two XFX 7970 Black Edition's. I have recently put both the cards under water cooling using the Koolance water blocks. Temps are fantastic.

I had a small'ish over clock of 1050Mhz (1000Mhz is stock) I'd left ram etc alone. This was on stock voltages.

I wanted to see what I could achieve within the safe zone.

I currently am testing....

Core Volts: 1181 mV

Power limit: +20%

Core Clock: 1125 Mhz

Memory: 1500 Mhz

I'm wondering what I can realisticely try that won't damage the card will under water with temps in the 30's while being maxed out.

What is a good OC testing utility?

Thanks

 

[StarScream345]

Awesome Video Card Bench marking:

Ungine Heaven - http://unigine.com/products/heaven/

PC Mark 7 - http://www.pcmark.com/benchmarks/pcmark7/download/

UNREALISITIC LOAD TEST! BE CAREFUL.

Furmark - http://www.ozone3d.net/benchmarks/fur/

 

[Nathlm]

Ok I have a 7950 and I would say bump the memory clock up loads more, it can handle it, they are very capable of doing humongous memory clocks easily in excess of 1700mhz. Same goes with the core I'd say aim for 1200mhz or even 1250mhz with as little as possible Vcore as possible - Up to 1.25v is perfectly fine for heavy 24/7 use but I would stay under 1.225v just because I'm over cautious.

Also if you have overclocking enabled in CCC (or overclock on startup options checked) then disable it because if you go wrong on one of the clocks then it will save and it can be very hard to change it back.

I would also suggest BF3 for testing because for me it showed many artefacts that other games/benchmarks/furmark did not

 

[MikeGT2]

I've furmark tested....

In afterburner

Core Volts: 1181 mV

Power limit: +20%

Core Clock: 1200 Mhz

Memory: 1600 Mhz

sounds safe?

 

[Nathlm]

I've furmark tested....

In afterburner

Core Volts: 1181 mV

Power limit: +20%

Core Clock: 1200 Mhz

Memory: 1600 Mhz

sounds safe?

Sounds perfectly fine, but have you got BF3?

If so then test it on that for about an hour, maybe even less

 

[ObscureParadox]

I've furmark tested....

In afterburner

Core Volts: 1181 mV

Power limit: +20%

Core Clock: 1200 Mhz

Memory: 1600 Mhz

sounds safe?

Might as well run a couple of benches like, 3D Mark Vantage or 3D Mark 11. That will give you a good indication on whether or not the overclock is stable.

 

[MikeGT2]

Thanks lads for your help.

I do have BF3... that's why I did this set up

I will test the OC... there is no problem with the temps I know that much..

Has anyone found what kind of tolerance these 7970's have with voltages?

 

[MikeGT2]

OK I just tried 3D mark 2011 and it froze. So I've backed down on the OC....

I turned off Overdrive in CCC and only used afterburner....

Core Volts: 1181 mV

Power limit: +20%

Core Clock: 1125 Mhz

Memory: 1575 Mhz

I wanted to hit..

Core Volts: 1181 mV

Power limit: +20%

Core Clock: 1200 Mhz

Memory: 1600 Mhz

But this is where I got lock ups. I tried increasing the voltage to 1187 mV but that did not help and I'm a little weary about

going higher.

Anyone have any suggestions please?

 

[Nathlm]

First see where the instability is (memory or core clock). You can do this by raising core first ~10-15mhz each time and checking stability.

When the card becomes unstable then go to the last that worked and from there increase in 1-2mhz steps again testing for stability each time.

After you have found the max stable clock for the core then do the same with the memory.

If you cannot hit the clocks you want then try more volts (1.2-1.25v is perfectly fine for 24/7 use) and increase from where it got instability from the lower voltage.

Note: If increasing the voltage doesn't seem to pull up the clocks then you may have found the limit for the card.

Hope this helps!

Edit: I personally wouldn't go above 1.225v but it's all down to you

 

[MikeGT2]

Hi,

ok.... this is what I needed to get 1200Mhz

Core Volts: 1231 mV

Power limit: +20%

Core Clock: 1200 Mhz

Memory: 1650 Mhz

hmm... safe? well I've seen people mention that max is 1.3v.

This gives me a 3D Mark 2011 graphics score of 20348 (this is 2 cards in CF)

 

[Kyze]

Just got mine too and im in the asme state as you.

Though i got a reference cooler and yours seems much better, at stock voltage i only get

Voltage: 1174mV

Powerlimit: +20%

Core: 1075 MHz

Mem: 1550MHz

havent played around with the voltages yet..

1100 core istn stable in heaven bench