Cudaminer - Auto setting problem with 2 cards.

[peri]

Hi,

I have 2 680's, and letting Cudaminer automatically find the best settings for each card individually, it tells me 16x14 is ideal - which it appears to be. If I run one of my cards at that (either one), it'll give 200+ khs.

Trying to run both cards at the same time (with -H 2 -d 0,1 -l K16x14,K16x14) and the rate drops to around 0.7 khs - whats going on?

The only config I've found that gives anything other than either <1khs or a crash is 8x24, and that tops out at about 220khs with both cards running.

Any ideas how it can be improved?

Thanks