I have had some ongoing issues with a set of dual 3.06 533MHz 512K Xeon CPUs. I have just bought a new set of components to build around these CPUs that I had in my possession. ASUS PC-Deluxe MB 4 GB RAM Dual CPUs (XEON, 3.06 533 MHz 512K) FC5 installed OS with raid, LVM Issue: I built the system, finally have the hard drives configured as I want, now ... the system just starts to hang while away, or crashes along the way. A couple of times recently though, during boot I have gotten some CPU warnings ... similar to what I have seen in the past. In addition, the system will just seem to lock up on occasion. The CPU checks that are run at boot time ... shouldn't those errors show up more often, or does the phase of the moon sorta thing have to be just right for a crash like that to occur? What is odd though, I ran a couple copies of this heavily intensive CPU application (mprime I think it was) ... ran for over 12 hours ... with both CPUs buried - no errors, but then some time later the system just crashed heavily. Things I have already considered: - over heated CPUs ... brand new coolers, used thermal grease - bios monitoring shows temps to be reasonable - at least when I can get in to check on them. - power supply ... bought decent brand, not cheap one. - UPS ... plugged into APC 420 SmartUPS (no indication of overload), shares this with another tower. Other thoughts and suggestions? I NEED this system up and running soon for work (heavy CPU related activities). Thanks in advance. Randy p.s. Any suggestions on a good location to purchase a matched set of these CPUs? I have been looking on the web - pricewatch - and they only list single CPUs. These are slightly older technology ... so tougher to locate.