Overclocking my 6970 lowers benchmark scores. Why?

[dacca]

Hey there, just spent all morning overclocking the gpu core of my 6970 and it has lowered my 3d mark vantage and 11 score. Why?
my rig
ocz 700w psu
bulldozer fx 8150 oc @ 4.2ghz
6970 oc @ 950 core and stock mem
gigabyte 990fxa-ud7
3 hard drives all sata 2
2 dvd drives
thats about it really
all latest drivers
not running cool n quiet
not sure what other info you will need to help. So hope this is enough

 

[Rustyy117]

It could be that 950 Core is slightly unstable, try the benchmark again at 925 Core an see if thats any better. Also set powertune to +20 in CCC.

 

[dacca]

I tried at various increments and ran furmark for around 10 minutes at each time on highest settings with full AA to really test it. No artifacts whatsoever, no stuttering. Seemed all good.
Would raising the mem make more of an impact on benchmarking than the gpu core?
What exactly is powertune?

 

[Rustyy117]

So did you run the benchmark at 925?

Core frequency tends to have more of an impact on performance.

AMD's whitepaper on powertune technology: http://www.amd.com/us/Documents/PowerTune_Technology_Whitepaper.pdf

 

[dacca]

Yeah, I ran benchmark at every 15-20mhz increase. There was no real noticeable difference. Then when It got to 950 it decreased my benchmark result by around 1000 points.
I have been getting low scores compared to similar systems on pretty much every benchmark I have been running on 3dmark11 and vantage

 

[Cygnus x-1]

It's due to instability in the overclock. The reason you're not seeing artifacts, is because of the error correction that is build into the card. That correction and chip instability sucks up performance, hence your reduced score in benchmarks.

I would reduce the overclock, going up slowly, only clocking the gpu or vram at a time. That way you know what is causing the bad overclock/performance issues.

 

[dacca]

Thats what I did man, I ran a benchmark at every 15 to 20mhz as stated in my post above, and ran furmark after every increment of 5mhz

 

[Cygnus x-1]

Do you have all overclocking in ccc disabled and set to default?

 

[dacca]

The only option I have is graphics overdrive enabled or disabled.
When disabled I have no option to overclock.
When enabled I can overclock.

 

[Cygnus x-1]

Personally, I would disable and use Afterburner

 

[dacca]

I will give it a go, but, if I am overclocking using that and checking it at regular stages and I am seeing no performance increase then how will changing what program i use help me?
I dont understand, surely if it is overclocked it is overclocked

 

[Cygnus x-1]

Some programs do a better job than others. Plus afterburner lets you voltage tweak if you so choose. In my experience, ccc is decent for mild overclocks, but to really push the card, afterburner will work better.

 

[vexun11]

My guess would be try upping the voltage? I just added a second 5830 and it sucks cuz I can't overclock them anymore