Thanks for all of the help Nick!
I got my i7 950 to 4.2GHZ, CPU Voltage-1.30625, QPI/Dram Core Voltage-1.34375, Dram Bus Voltage-1.66, CPU Ratio-21x, BCLK Freq-200, Dram Freq-1603GHz, Memory Timings as suggesed, all other settings exactly as you suggested, either Enabled, Disabled or Auto.
The above ran OCCT for an hour with no errors last night and Prime95 overnight for eight hours with no errors.