Strange 2x 6950 crossfire behavior (OC'd)

[arachn1d]

So I overclocked my cards (unlocked and clocked to 840/1325) and I was testing out the overclock in battlefield and I noticed my frame rates were a lot lower than BEFORE the over clock. I'd usually get about 50-70fps with 6048x1200 max settings besides the bloom and now I'm dipping below 30 very often... even in vietnam and that was never the case!

I'm not sure what's going wrong?

In afterburner it says my clock is 840 in the graph.

What's odd is I'll load up the TechPowerUp GPU-Z and the sensor only ever says 500MHz and 1250 MHz but that may be because it is broken or it can't read it when I'm alt tabbing to view (out of the game).

Why would the overclock reduce performance? I also set CCC @ 20%.

I actually OC'd my CPU as well to 4.5GHz (2500k at 1.35v)m and I'd expect an INCREASE in fps not a DECREASE.

I'm so confused right now.

* other things I did:
** Install AMD Catalyst Profiles
** Manual Fan speed control so it never goes above 75-80c.

(note: I noticed with the overclock I'm getting a lot higher frame rates in mafia 2 than before the OC... so... another odd thing).

(note 2: apparently GPU load is at 99%?)

 

[sirmonkey1985]

performance difference i don't know.

the reason you see the 500/1250 when you alt tab is because the cards automatically switch to multi-screen 2D clock mode. but the graph should obviously show a drop/spike when you alt tab back into the game. if its not then it sounds like its not going into 3D clock mode.

the mafia 2 performance and the 99% gpu load is a good sign though.