My PC is made up of a P8Z68 mobo, i5 2550k OC'ed @ 4.1GHz, and a GTX 560 Ti OC'ed. Proper voltage is given, and this is freaking/scaring me out. Idle, or on I.Explorer, fine. Max temp of 42*c. Right now (since 1 hour ago) I have been rendering a 1080p 60fps 17minute video in Vegas Pro 11 and immediately (under load) it just ******* JUMPS up to about 80% and higher loads, and is @ 90c. This is boiling it, isn't it? How do I solve this? I actually have a H100 cooler, yet am using the stock intel fan. Should I use the H100? Seriosuly I have it RIGHT now...
With an OC like that, and that you've "given proper voltage" (read: raised voltage), you should certainly not be using the Intel stock HSF. Install your H100 and that should drop your temps like a stone.
One thing that I would double check, is to make sure that the heatsink is properly attached/mounted to your motherboard, as I know (from experience) that that can make a big difference. If possible, try to look underneath your motherboard and check to make sure that all four of the push pins/screws are showing underneath.
And also make sure that you have thermal grease on the cpu/heatsink.
I had a very similar problem with a computer I had a few years back- it was freezing in pretty much the same way as yours. It turned out to be a combination of the fan on my graphics card had packed up, causing the graphics card to overheat, and the cpu fan on the heatsink was packing up - it still looked like it was running properly, but when I went into bios, it showed that the rpm was no where near as high as it should've been. It then completely packed up. Once I had replaced both fans, the freezing problem stopped.