I recently thought I had a stable system, p4 2.8@3.43, 3dmark2001/03 good, and other benchmarks completed fine too. I starting getting crashes with some gaming and video editing, and decided to try prime95, and found out I was unstable less than 1 min into it. I went to stock and it was fine. I always left the vcore and ddr voltage at auto. Under cpu-z it read my vcore to be at 1.575, which is weird because I thought default was 1.525. I decided to up both, and took the vcore to 1.6 and the ddr voltage to 2.75. I ran prime95 only for a few minutes, but that did seem to correct the most obvious error (I will run a longer test overnight). However, in cpu-z the vcore which I set to 1.6 in the bios, is now readin 1.664. I have a p4p800 deluxe, which I know are screwie to say the least as far as reporting temps are concerned, just wondering if this is the case as well for other things too. Also, what's the dangerous voltage range for my cpu?

I'm not an Intel guy so I won't offer any advice about max vcore settings. But sometimes, the board "overvolts", so even though you may have it set at 1.6v, it is actually 1.664v. The vcore on my Asus A7N8X-X is set at 1.70v, but both CPUZ & Asus Probe report it as 1.744v

Some P4P800 and P4C800 boards are overvolt slightly, and if you have a good PSU giving nice 12-volt rail you would end up a bit more also. It's even better that your 2.8 could run with only such a slight vcore increase to hit 245FSB; shouldn't be complaining.

Well, the thing is it's now getting errors at that voltage too, via prime95. What is an usual voltage for this oc, range that is? I have a zalman 7000-cu, 5/4 ratio on pc3200 dual hynix ram, even a non stock NB cooler, I think I should be able to do this oc...

I have never been lucky enough to have any processor overclocked to what some people are saying/advertising. My 2.8C with 1.7 Volt using P4P800 Deluxe is primestable at 250FSB. The 2.4C also at 1.7volt with IC7 is primestable at 270FSB. Yes, I have to add NB fan to the passive Asus NB cooling. This is much needed with another system using 2.8E Prescott at 250FSB.

Did you need 1.7 to be stable at 250 FSB? How did you realise this, was it not starting before that increase, or was it just not stable? I've heard 1.7 is puching the limit on what you should up a p4, is this true? What are you temps? Also, are you 1:1 or 5:4? I'm going to try maybe 1.65 for now and see what that does, if it makes me stable for a bit longer, than I'll know I guess that it's lack of voltage...