Cheers guys. I did just that and it works great
Next question, whats a reasonable oc on a 5850 at stock and a 5870 at stock? Or to put it another way whats the average hash rate I should be trying to achieve???
5850 = 400-420 MH/s
5870 = 435-460 MH/s
So around what core speed would I be looking for?
You won't see those speeds until you hit around the 1 GHz mark. My 5870 was just over 471 @ 1015 core / 330 memory. There is generally a formula to calculate how many mhash you can do given a certain amount of stream processors and core speed on VLIW4 cards.
1 stream processor @ 1 MHz will do about 290 hashes/sec, so just scale up from there. 5830's have 1120 stream processors, 5850's have 1440, and 5870's have 1600.
So take your 5850's, say you want to run at 950 core.
290 hash/sec x 1440 processors x 950 core = 396,720,000 hashes/sec or 396.72 mhash/sec.