Overclocking AMD graphics

[miniyazz]

What's important - core clock or memory clock? Or both?

For folding

Card in question is an HD280x.

 

[Stan_Lite]

I only have Nvidia cards but I would imagine AMD would act similarly. Core clock makes a big difference, memory clock makes a marginal difference. I would concentrate on the core clock if I was you.

 

[miniyazz]

Thanks, turns out I can shove both core and memory up to 11 and all seems well for folding!
(Using MSI Afterburner, maximum overclock is just over 20% up from stock)

 

[hanluc]

might be worth lowering the mem for reduced power/heat, very often it makes no difference to the performance. I'm not 100% sure with regards to folding though.

 

[miniyazz]

Figured out how to overclock beyond those limits, looks like 1125 (core) is the limit before Furmark has issues - interestingly Borderlands 2 doesn't like it beyond 1075
1125 up from 850MHz

Memory went up from 1500 to 1800 and I've not reached a point where it doesn't like it, just didn't fancy pushing my luck!

All this is on stock volts, I can't seem to get Afterburner to allow me to adjust the volts at all. Temps staying around 75ºC at the moment so not a huge amount of leeway anyway with my i7 pumping out heat also, but not high enough for me to think about knocking back the memory clocks

 

[RHS]

Depends on the card, my card was already factory clocked hard and I overcooked it a little bit to the stage I occasionally get graphics tear on the screen, still works thou.

 

[miniyazz]

I'm starting to get a little sceptical at how effective Furmark is at testing graphics cards. Had a little tearing with high memory clocks in game and with folding neither of which should stress it as hard as Furmark so back to a normal memory o/c of 1550

 

[miniyazz]

Just to update on this, ran F@H on A17 for a couple of hours on core 1125 mem 1500 with an average % time of 08:12 (fluctuation between 08:03 & 08:25, seems to go up and down roughly alternate %s)
Then part way through the WU underclocked memory to 1300 and for the next few hours got average % time of 08:22 (fluctuation between 08:13 & 08:37, similar pattern).

So my conclusion is that memory clock increases processing speed by ~1.2% for every 10% overclock
Your mileage may vary and of course it may depend on the WU and also the absolute memory clock in relation to core clock, e.g. at extremes of memory clock the effect may be different..