I run at 900Mhz for 26 hrs and during that period, performed a myriad of tests .. all seemed fine.

I however had 1 shutdown at the end of the 26th hour. After restarting, everything was normal..... not sure if the shutdown was temperature related (room temp was 34 degrees at the time).

I have now dropped to 800Mhz. It's still very zippy and I'm ok at that speed (not that much difference in general use).