Ka-ching! I, too, would suspect heating the upgrade card. In fact, i experienced that even with a Mercury 1.4 GHz single processor CPU card. I did not get Kernel panics, but I got weird bright green font substitutions all over the place. Then, I got freezes that necessitated manual powering down. --Steve (now on a 20" Intel iMac) At 4:23 AM -0500 12/14/06, MegaSTMac at aol.com wrote: >I'm running 10.3.9 on a QS with 1.5 Gigs ram, dual 1.8GHz upgrade card, At 7:08 AM -0500 12/14/06, Rick Smykla wrote: >If you haven't changed your hardware config lately, it could be overheating, especially since the dual 1.8 is an overclocked CPU to begin with. I had this problem with my GigaDesigns card (purchased early this year). The company replaced the card after asking me to do a voltage (jumper) change and some additional testing. In my case, I run the folding at home client software, which maxes out the CPU usage 24/7. I didn't see any problem with this card until the warmer weather appeared, and I wound up setting the card to 1.6 GHz to keep it stable. I eventually contacted the company with a description of the symptoms and they supplied me with a redesigned card, which has performed well and without problem at the rated 1.8 GHz.