can't clock memory to advertised frequency

Hi,
I have a P5E3 Premium and just got 2*2GB of Corsair TW3X4G1600C9DHX. I read on several forums that the timings will have to be set manually for this RAM.
The first time it booted, gave me a post of DDR3 1066MHz. Fine I went into the bios, set the timings to 9-9-9-24, set the volts to 1.8V and rebooted. It posted 1600 MHz this time and all seemed well. I ran memtest86+ at this setting for 2 hours without any problem!

Now here's the problem. I had to test a friend's CPU on my system. After that was done and I plugged back my own CPU, of course the bios settings had to be re-done, which i did. However this time around, the system wont boot! I tried repeatedly but in vain. Kindly help me with this.

my config:

P5E3 Premium
E8400
Corsair 1000W PSU
DDR3 (seems buggy)
2*4870X2
and all the rest...

oops sorry i guess i didn't state it clearly. I've cleared the CMOS and the system boots at the default frequency fine. However, I can't get it to post at 9-9-9-24 with 1.8V now.