i7 920 overclock

[thephilosophizer]

So my sigs got the details. I've got the chip cranked up to 3.99ghz @ 1.275v
The ram is underclocked to 1520mhz (it lets me pick either that or something around 1800).
I managed to get booted at 4.2 and 1.3v with the ram at 1650mhz.
I didn't want to go above the 1.3v level, but I do think that I could get her steady with a higher voltage, but I also don't want to sacrifice the long life span.
And the temps. Right now I am running at 40-45 idle, and up to 75 peak load. Is that too hot, and what should I try to go for?

[JLK03F150]

That's a nice looking system & what looks like a good 24/7 overclock. From what I've read, 75C load temps are fine, and you still have some headroom.