NEWB: Lower mining speed when idle

[psilan]

 

Hi All,

I just noticed that I seem to lose about 100MH/s when my machine idles down.
Does anyone know what causes this?

I can see if from home 450-499, but then fiancee gets home and plays Home and Away (eugh) and it's now chugging along at ~550 minimum.

Should I be using some kind of anti idle?

Running ASUS 5830x2. In crossfire. Not overclocked. Guiminer -v -w128.

Thanks!