I just picked up a 400MHz Sawtooth that I'm using as a file server running OS X Server 10.4. It's fine except that it locks up every 12-48 hours on average. It's a hard lock - mouse pointer freezes, nothing in the syslog, and then a few minutes later it reboots because I have "Restart after a freeze" checked in System Preferences. I have noticed that it seems to only happen when I am VNC'ed into it. Could the VNC server (Vine Server) be causing it? The specs are: 400MHz G4 (See below about the RAM) Firmtek Seritek 1V4 PCI-X SATA card Intel Pro 1000 PCI gigabit card 1 master and 1 slave Seagate Barracuda III ATA drive 2 Hitachi T7K500 SATA drives I first suspected a RAM problem. I have like 10 128MB PC133 DIMMs from spare parts on hand, and I can't be 100% sure that they are all good. I first tried with 4 DIMMs, 512MB. Freeze after ~24 hours. Swapped those out with 4 others. Freeze after ~12 hours. Took out two of those, running w/ 256MB. Freeze after ~48 hours. Swapped out those two with two others - another freeze. I took out the video card and modem since I don't use them anyway, same freezes. Just now I took out the network card (Intel PCI gigabit) and am using the built-in, just to see if that could be causing it. If that doesn't solve it, I'll take out the Firmtek SATA card next. If THAT doesn't solve it, I'll swap the logic board I guess. I'm already suspecting the logic board... my question is, my Sawtooth has a 1st revision board, with the uni-N revision 3 chip that doesn't support dual processors. Can I replace it with a 2nd revision board with the uni-N revision 7? I know that the PSU in the Sawtooths that came with a rev7 board was 228 watt, as opposed to the 200 watt unit I have, but will it still work? I don't think I need a high-wattage PSU since it's only a 400MHz G4 and although I have 4 HDs, they only use about 6 watts each and do staggered startup and I have no video card or optical drive installed. Also, I noticed that the PRAM battery is totally dead. I've got a new one on order. Currently running with no PRAM battery. Might that be an issue?