6950 on Linux, unlocked shaders, hash rate lower than expected

[Mr2001]

I'm running a 6950 on Linux with the latest fglrx, and I've used RBE to unlock the shaders and increase the clock to 900 MHz.

When I start poclbm, the hash rate climbs to around 410 Mhps during the first few seconds, then drops down to about 353. According to my sloppy math, I should be getting something like 385 with these tweaks, so I'm wondering what the problem is...

Are my expectations too high, and 350 is right, and the brief display of 400+ Mhps is incorrect?

Could the card be throttling itself for some reason? It's not overheating, the temperature stays around 68C with the fan at 75%.

Could the shaders not actually be unlocked even though RBE says they are? It's this 2GB MSI card which is supposed to be unlockable. Is there a way to check how many shaders are active without installing Windows or moving the card to a Windows box to run GPU-Z?

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[fitty]

In Windows you have to make sure the 20% overdrive is on. I'd assume that goes for Linux.

If that gets reset to the deault of 0% then I drop from 400 down to 345 like you said. Fixing that puts my speeds back up. For some reason in Windows it gets reset sometimes (using MSI Afterburner). I'd see if that's an option in linux and adjust it. =)

[Mr2001]

Ah, got it. That Power Control option isn't exposed by aticonfig, but I found this thread with code to turn it on. Now I'm at 388 Mhps and 70.5C.