So we were working on getting my friend's PC stable at 3.8 GHz, which is using a Gigabyte X58-UD3-R, i7 920, 6GB RAM, a Corsair 750w PSU and a Thermalright cooler. Everything was fine, we were about 15 minutes into LinX testing, processor was running at 71C. I went to open Chrome to show him a website, and the PC shut off. 2-3 seconds later, the smell of burning electronics filled the room. We don't have an extra X58 system here to test, so we are trying to figure out what is wrong. I don't believe it was the power supply - his system doesn't draw near 750w. There was no pop or noise when it shut off, it just powered down. But we can't narrow down the burning smell to a particular component. I'm thinking we burnt something on the board, or possibly the i7, but I have subjected my i7s to a lot more abuse than he has and no problems yet. Suggestions? We tore it down but nothing is obviously broken.