Asus P6T overclock fail

I had installed a new set of Corsair DDR3 modules (TR3X6G1600C7D - 6Gb) in my PC.
I had a set of OCZ modules but one failed and to get an RMA I have to return the full set.
Running an overclocked i7-920 @ 3.8GHz in a Asus P6T motherboard using Vista 64bit
Turbo is off.
Running AI Overclock Tuner - Manual
CPU Ratio - 19
BCLK - 200
PCIE freq. - 100
DRAM freq. - 1603
UCLK freq - 3208
QPI Link - 7218
cpu voltage - 1.325
ppl - 1.88
QPI/DRAM - 1.325
IOH voltage - 1.10
IOH PCIE - 1.50
ICH voltage - 1.20
ICH PCIE - 1.50
DRAM voltage - 1.64
Turned on my PC yesterday morning and I got a "blue screen" then the BIOS shutdown and reported overclock failed.
My PC finally booted up and my cpu frequency is now 2.53GHz.
I contacted Corsair and they suggest setting the DRAM freq. to either 1066 or 1333
I have not done anything as yet.
Are my overclock settings OK apart from the DRAM issue?
What are your thoughts on the DRAM frequency that Corsair suggest?
Should I set the AI Overclock Tuner to XMP?
Probally does not matter but I'm running BIOS ver 0403.
Turned back on agin this morning and BIOS has reverted back to factory defaults.
Now the cpu is at it's dfault setting of 2.67GHz
Hopefully somebody has some ideas what I'm doing wrong or something!