O/Cing lowers Mhash

[staraptor]

Anyone else had this?  At around ~880 clock, the cards I have been using are pushing around 350Mhash.  When I bump the clock rate up higher, say 900+, the mhash rate goes down (sometimes by nearly half).

[zargon]

Anyone else had this?  At around ~880 clock, the cards I have been using are pushing around 350Mhash.  When I bump the clock rate up higher, say 900+, the mhash rate goes down (sometimes by nearly half).

are they being throttled down due to heat?

[staraptor]

doubt it - it's simply a matter of when I increase the clocks, the Mhash drops o.O heat was at 74c

[c0m47053]

Perhaps the card is just unstable at that clock. Does Furmark or similar run without artefacts?

[MBH]

Which card are you using?

Some cards' firmware throttles the processing to reduce emitted heat, as already mentioned.