dirtynammer :
my core i7 930 seems to be the reject out of all the chips made as it behaves pretty wierd compared to other chips. I have it overclocked with HT on, and it idles at 39 which is great but at load with prime blend test temps reached close to 80, which seems like a pretty big jump to me but whatever. My main concern however is when I ran prime for 8 hours, I had an error on core 4 six hours into the test. Should a be worried about this? most people unless they are true enthusiest wont run prime for more then 3-4 hours.
That is exactly why you stress test with prime95 or whatever.
Some chips are better than others. You got one that makes an above average chip possible.
You did well by testing for long enough to flush out an error.
What can you do?
1) Back off the overclock a bit. Do you really need 4.0?
2) Heat is a prime reason for limiting overclocks, and 80c. is high. Try reseating your cooler. Most people use too much material and it acts as an insulator.
I imagine that you have a good oem cooler; the stock coolers are not that good for overclocking.
3) Raising the cpu voltage a bit could help, but read a bunch to understand what you are doing first.
4) Each HT gives you about 1/3 of a core extra cpu power. It is of use only if you are heavily multitasking and consistently use all 4 cores plus the hyperthreads.
You can usually get a higher overclock by disabling hyperthreading.