What to look for in benchmark-tests when overclocking GPU?

[Hobopotamus]

Hello.
What exactly am I supposed to look for when judging if I should continue overclocking my GPU?
I am using "Heaven 4.0" and slowly raising the memory clock on MSI Afterburner. So far I'm up to 550, and I haven't noticed anything that wasn't also there, when it was on the default.
I am not raising core voltage, only memory clock (and after that core clock).
Thanks in advance!

 

[coozie7]

You're working the wrong way round: Do the core first, then memory, then core again because the tweaked memory will usually allow a higher core clock.
Be aware that too much memory OC will result in lower performance as the cards built in error correcting system starts to work harder.
Too much core speed will result in artefacts or crashes.
In all cases keep a close eye on the card temperature, stay below 80C for Nvidia (higher and the card cuts back its Boost speed) or 85C for AMD (you can go higher but it'll get noisy and can shorten its life).
Messing with the voltages is the quickest way to fry the card and even tiny increases dramatically increase the heat output.

And you are looking for a increase in frame rate with each change and benchmark run.

 

[oskerw]

Aside from stuttering and tearing, look at the core clock curve in afterburner. Make sure it stays at 100% and doesn't have periods where it drops down, as it's throttling from temperature at that point.

 

[Hobopotamus]

Hi.
Thanks for the answers, they're of great help to me.
I followed your advice and started overclocking the core first. I set it to 150, and didn't notice anything different from the default. Therefore I raised it to 160, and it still seems fine to me. The core clock curve is stable at 1489 when benchmark testing. Does this seem realistic, or am I just not seeing the faults that occur? And is there a level which - whether I see the faults or not - it is adviced to not go any further?
Thanks in advance!

 

[oskerw]

160 MHz doesn't seem unrealistic. I don't know what card you have but I can go from 960 to 1200 MHz on my 7950. Further and my computer just crashes. When I had an Nvidia card the display driver would crash if I went too far. Look at the overall GPU usage curve too.

 

[Hobopotamus]

Hi.
I'm sorry, for some reason I forgot to specify that. I'm using a MSI GTX 970 Gaming 4G. I tried 200 MHz, and the core clock curve remained stable. As did the temperature, which lies around 66-67 constantly. The GPU usage shows that there are times at which it falls from 99% to around 30%, but it's very short periods before it rises again. The result it got me was a higher score on the Heaven 4.0 benchmark test, so it seems okay.
The fact that the GPU usage drops isn't a problem, right?
Thanks again for the help.

 

[oskerw]

Yeah it seems normal since the card is still running pretty cool. 200 MHz ain't bad!