I finally received my 1.6GHz G5 system last friday after a long wait. I ordered the system with 256MB RAM, hoping to avoid paying a steep premium to Apple by using 3rd party RAM. I initially bought 2 512MB sticks of Apacer PC2700 CAS 2.5 DDR SDRAM. I installed them, the system booted up fine, but would kernel panic or just plain freeze up after 5-15 minutes of use. I swapped the Apacer DIMMs out, and tried a pair of Kingmax PC2700 DIMMs instead from a friend's system (btw, the Apacer DIMMs worked fine in my friend's nVidia nForce2-based Athlon motherboard). It was the same story with the Kingmax DIMMs, with unrecoverable freezes bringing down the G5 after only 5 minutes or so, even if it wasn't doing anything taxing. Has anyone had any success upgrading the RAM in a 1.6GHz G5 system? If so, what brand of memory did they use? Apple seems to have used Hynix DDR333/PC2700 CAS 2.5 DIMMs in the G5 1.6GHz systems. I have also run the Hardware Test that comes on the OS X restore CD, but it doesn't find any problem with the memory. Thanks, Mat.