ASUS 7850 - unexpected performance drop OC past 1000 mhz

[blin787]

Hi
I recently bought ASUS 7850 video card.
Using ASUS GPU tweak to overclock, and get very unexpected results - performance drops significantly when going past 1000 Mhz on GPU.

My config: i5-2500K @ 4.4 Ghz, ASROCK Z77 Extreme4, Crucial Tactical 1866 CL9, ThermalTake 630W smart psu.
I have latest BIOS, ASUS GPU tweak downloaded 2 days ago.

Testing 3dmark 11, Performance (720p)
In all tests RAM - 5500 Mhz.

Stock (860 Mhz) - P5490
900Mhz -P5626
1000Mhz - P6135
1001Mhz - P5292
1100Mhz - P5336
1200Mhz - P5344

ASUS monitoring utility shows my these exact frequencies - so WTF??

As this card is 10Mhz stock overclocked beyond reference, 3dmark scores suggest something like dropping to reference frequencies after going past 1000Mhz....

 

[notty22]

Did you go in to CCC and change powerturne to +20%. This has to be done or the card throttles when power pull in watts goes over a predetermined #.

 

[blin787]

Did you go in to CCC and change powerturne to +20%. This has to be done or the card throttles when power pull in watts goes over a predetermined #.

Thanks! Absolutely right. In previuos card I had (6670), I don't remember having powertune option

Now getting P6500 at 1100 Mhz