X090T Overclocking with M4N98TD Evo Mobo

Hi Guys

Anyone here help me out. Decided that after months of running everything at stock I am going to start to push for more out of my build.

Currently running

M4N98TD Evo
X6 1090T CPU
4GB Geil Black Dragon DDR3 1600 Ram
H50 Cooler
2 x 1GB GTX 460 SLI

And loads more components

Before I started I ran Prime95 as had niggly problems last month, been trying to narrow down whether graphics cards, cpu or mobo was at fault. Still unsure but ran 3d Mark Vantage and got 28000 so seems to be okay now.

I ran Prime95 and I had instant failure on Core 4 on first Test. By test 5 Cores 5 and 6 had failed. So only 3 functioning cores after 5 tests on Prime95.

To Note in BIOS all additonal settings are disabled i.e C1E, ACC, Cool and Quiet etc

I chaned AI Tweak to Manual and increased my Clock Ratio to 18. Prior to this the Turbo feature was enabled and that was set to 3600 but when upping my clock ration manually to 18x it wont boot to windows.

System restarts after saving BIOS Settings, inital beep is there when turning on, runs through summary fine but then nothing at all no windows logo screen or anything. Monitor still has signal hence blue light shining but other than that ziltch.

I restart and go back inot BIOS and put ratio back to 16 and boots up.
Any ideas. Could CPU be faulty???

Any one got time to help me out