Note that 3DMark usually doesn't crash your whole system when it goes down. Instead, it gives you a "file is corrupted" message. For example, i have a PIII 600 @ 840, and the only benchmark that failed at 1.70 V was 3DMark. The system was slightly unstable, but 3DMark crashed every single time. Now, when I run it at 1.80 (had to go there), the system never hangs, and 3DMark runswithout problems. I have also had those "file corruption" messages when I ran my Geforce at 160 with the retail (tiny) heatsink. Now I use a processor heatsink for that one.