I have just upgraded my G4 sawtooth 350Mhz with a new Sonnet Encore/ST G4 1Ghz card and it been working great. The problem I seem to be having for the past couple of days is OSX 10.3 keeps freezing up on me and all I can do too get the OS to respond is hard reboot. I did some asking around and it seem that this happens allot when the CPU get too HOT. It a bit odd that Sonnet do not supply a new heat sink to cope with the extra Heat. I am still using the same heat sink which come with my G4. According to Sonnet information they say that it will work fine with the new CPU. Does anyone here now how too stop the heat build-up with the new processor form freezing my G4. Any ideas are welcome.