[SMTP]

This is a litte odd to me. Full system specs in my sig, RAM is Patriot Extreme 1600. I've ruled that out by dropping it down to 1033 while testing, no dice. Now, the CPU will do 3.8 with just a minor bump in Vcore solid as a rock. I didn't even have to touch the other voltages. That's at 180 blck. As soon as I try to push that up to 190 it all goes to hell as soon as I fire up Prime (pretty much instant crash, striped pattern on the screen) and no matter what combination of voltage settings I try it just won't stabilize. The most logical conclusion to me is that I'm doing something wrong.

I have HT enabled, turbo mode disabled. One thing I don't get is 4.0ghz should = 200bclk but the BIOS reports 4.08 @ 191. It must be that the multiplier is at 21x but I thought these were locked at 20? Could that be the problem?

At 191 I tried Vcore all the way up to 1.4,QPI PLL 1.5 and CPU PLL 1.92. But I am by no means an expert overclocker. What am I missing?

[doz]

For testing purposes, disable C1E, Speedstep, Turbo, and anything else associated with it.

2nd, Stop messing around at 190. Goto 200bclk, 1.3V QPI, 1.65v on the RAM, leave PLL stock, and set your CPU voltage to 1.35 in the bios (high, but give it a shot).

See how that does. If that is stable, start lowering your CPU voltage until it becomes unstable. Also, you can disable HT if you want until you get stable, then find what you need to be stable w/ HT on, or just leave it on if you wish to use it.

[mattspalace]

What voltage setting are you using for the memory? My particular kit is 1.65v - make sure you have it set correctly.