The PLE133 will support Tualatins, but if I remember correctly some implementations have problems with the either the PIII Tualatin and/or the PIII-S 512KB Tualatin variety. Which board, revison and BIOS are you running? I can tell better that way. Unfortunately, I have a pair of the 512K server chips and I'd do them for 30.00 plus shipping each. I still have a 1.0Ghz PIII non-tualatin with a heatspreader in one of the test boxes. I could test it this weekend, if you'd like. I should have some slower PIIIs for a pittance as well.