Can I Overclock my 6950?

[lukebussey]

Hi all,
I'm new here so please don't go mental if there's already been a post with with a topic along these lines about the same card - I really want to know about your opinion on my specific settup and card!

I have a Saphire 6950 2GB Dual Fan "OC Edition" which I bought here months ago, which has served me well as a GPU, but I want to actually overclock it now that I'm happy with it running stable at stock clocks.

At stock (currently) -

• The card idles at 39-41C (Is this bad? It's WAY higher than my CPU idles but people say that GPUs are hotter by nature... I have no idea, please elaborate?)
• Under load with furmark I can get it to a max temp of 69C (Innuendo unintended) but it averages at about 67C throughout half an hour or so of 100% load very stable with no fluctuations.
• The fans run at about 27% at idle, and under 100% load they were running at 40-48%. Is this good/normal?

I'm scared to raise my clocks because looking around, people are saying they don't like going above 75C, and I'm almost at 70 with stock! Is this bad? Am I doing something wrong?

I think one of the problems may be that there's no extraction fan on my case near the GPU. There is a 200mm intake (bottom front of case), and a 200mm & a 120mm outtake (both at top back of case).

If it would help allot, I could mod my case to put a fan on the side window of the case next to the GPU to extract hot air? My case is a CoolerMaster Storm Enforcer if it helps. I'd put the fan on the transparent bit on the side (see picture)

http://images.tweaktown.com/content...rm_enforcer_mid_tower_chassis_review_full.jpg

Any advice on whether or not my GPU temps are good, whether I should overclock/how/by how much, whether I should add a side fan (thus voiding case warranty), and how to improve cooling performance would be greatly appreciated!

Thanks,
Luke

 

[tommybhoy]

85-90c is within safety margins(104c is the throttle temp iirc) so your temps are ok.

Forget about Furmark-Power virus that stresses the life out of your gpu, gpu's don't like it at all.

Gaming temps-these are the temps that count, not Furmark.

Go into CCC, or download and install MSI Afterburner(switch OSD on in options and enable gpu core temp display)/Trixx and manually adjust your fan to 100%(it will sound like a jumbo jet, but better safe than sorry when you don't know what your doing)add +20% to the power tune slider, then bump your gpu clocks up to 850-870Mhz, should be stable and use something like Heaven 4 to stress the clocks.

If it's fine, keep going in small steps of +20 on the core, when it starts to sparkle/spike/crash, drop the clocks back -20.

Reset the core clock and try the vram on it's own the same as above.

When you know what each clock is stable, apply both and test again, dropping off a touch if it's unstable.

Either test again on the automatic fan profile, manually set the speed or make a fan profile curve within AB.

A side fan could decrease airflow inside your case, so leave it be for now.



Do the above and check temps, if they don't increase much, come back and ask about voltage clocking.

 

[Devrij]

The above is all solid advice. Furmark is an unrealistic test, and I would avoid it.

Although I like to keep my GPU under 80C under load, the VRMs can get hot as you load more voltage into the gpu, which can cause artifacts and crashing over certain temps (I saw mine hit 105C once). For that reason, it's also worth installing GPU-Z (free) which under the sensors tab shows all the info such as actual input voltages, VRM and GPU temps, memory usage etc. A lot of that is covered in afterburner, but the VRM temps can be worth looking at if you find your crashes or artifacts are related to VRM temps. Sometimes reducing volts can fix that problem (usually, instability -> pump more voltage in). That is generally only an issue with very high overclocks though, so see how you get on with the steps tommybhoy outlined above.

Also, keep in mind you can adjust your fan profile in afterburner to be more aggressive at high temps to keep them down if you don't mind the noise.

 

[C64]

The gains are quite small overclocking 6950/70's I don't think it's worth the potential instability.

It's worthwhile bios flashing a 6950 to a 6970 though to get more shaders.

 

[Rilot]

It's worthwhile bios flashing a 6950 to a 6970 though to get more shaders.

You're better off flashing the 6950 BIOS that has unlocked shaders rather than the 6970 BIOS. The VRAM timings and voltages are different on the 6970 and there were reports of cards biting the dust.

This all assumes that his 6950 doesn't have permanently locked shaders. Many of the later cards did.

I flashed the unlocked BIOS in to my 6950 and it yielded a decent performance boost.

 

[tommybhoy]

The gains are quite small overclocking 6950/70's I don't think it's worth the potential instability.

Mine unlocked@1GHz(25% oc) were putting 570's to the sword and faster than stock 580's, might not be worth the hassle, but the op asked so I imagine he wants to give it a shot.

It's worthwhile bios flashing a 6950 to a 6970 though to get more shaders.

It might already be flashed, some of the dual fan editions came unlocked on the second bios out the factory-not just the Toxics.

 

[BaNksY IV]

Judging by the original post I don't think its wise suggesting he flash the bios at all (no offence original poster but I wouldn't want you to brick your card) also I found that you get a decent benefit by overclocking the 6950 and little benefit over unlocking the additional shaders so my advice would be to overclock either with MSI afterburner or Sapphire Trixx.

 

[Davedree]

Judging by the original post I don't think its wise suggesting he flash the bios at all (no offence original poster but I wouldn't want you to brick your card) also I found that you get a decent benefit by overclocking the 6950 and little benefit over unlocking the additional shaders so my advice would be to overclock either with MSI afterburner or Sapphire Trixx.

Not gonna brick as the card has dual bios, But yeah you're right there are more gains from clocking than unlocking the shaders. (Although like mine unlocking and clocking to 930/1375 gives a lovely boost in games).

 

[Davedree]

Mine unlocked@1GHz(25% oc) were putting 570's to the sword and faster than stock 580's, might not be worth the hassle, but the op asked so I imagine he wants to give it a shot.



It might already be flashed, some of the dual fan editions came unlocked on the second bios out the factory-not just the Toxics.

exactly flick the switch and see if you got a lucky card.

 

[andy_mk3]

The switch on mine switches the output between some connectors I think and has nothing to do with the BIOS. Mine is unlocked to 6970, but I bought it that way.

Mine will overclock pretty far, will do 950/1500 no problems.

 

[lukebussey]

Wow, I was not expecting this many replies! Thanks for the information everyone, it's all been acknowledged and I'll give everything mentioned a shot tomorrow!

My card is a dual bios one, but did not come unlocked by default so I never touched the BIOS so I'll give that a try to see if I can unlock a few shades!

I'll go for TRIX over afterburner because it's made by Sapphire who made my card (or does this not matter, is AB better?)

Thanks VERY much to everyone who's responded, I genuinely appreciate your time allot!