my GPU usage (and thus hashrate) has always fluctuated like a small sine wave from 99% - 90% , after this patch, they all stay a straight line 99% , so that's way more than a 3% increase in hashrate for me.
What's weird, mine went from 90%-96% to 96% straight but the added performance adds 1.5C to the temperature, I might have to clock down a bit to get tot he previous 90C stable line, which means I am forfeiting the benefits of the above optimization. At least I use less energy, the Earth will thank us all...Same here, actually. I was ok with 6870 overclocked to 1000 MHz, but after the change it became unstable so I had to go down to 975, which is kinda sad. Yet, I blame it on poor ventilation in my case, so may be I'll get it running at 1000 again, eventually
Just run the card with open Case.
Also a good improvement is add 2x 120mm 10db-Silent Fans, that cool your card more Silent.
I run my 6870 @ 1005Mhz , 60 degrees Celsius , 60% Fanssped (card fan) @ 302Mhash/s.
(now with speedfix @ 311Mhash)