I've been reading the posts and just thought I would throw my 0.0006369BTC regarding temps, psu and hash speed...

I use 1 HP Common Slot 1200W Server PSU with a Gigampz BB per SP20.  I'm not concerned with noise and power is cheap.  I am guessing that the spikes in the "last day" chart is the SP trying to auto correct for the PSU but I'm not sure.  If anyone has some thoughts I'd welcome them.

http://i58.tinypic.com/9gafb9.jpg