I recall some discussions about how to test your Mac's memory and this may be the answer. The 7-Dec-04 MacFixIt daily update had the following buried in the text (not a headline). Rember 0.2.2b: GUI wrapper for the Memtest CLI memory/RAM tester I went to Version Tracker and downloaded the very neat utility. http://www.versiontracker.com/php/dlpage.php?id=24508&db=mac&kind=&lnk=http% 3A%2F%2Fwww.kelleycomputing.net%3A16080%2Fdownloads%2FRember.dmg The blurb says " This is a GUI I designed to run the "memtest" application." Just ran Rember and it confirmed my the 256K DIMMs are doing their job. BTW, mine are mixed 2 PC100's and 2 PC133's in a G4-450 AGP. Every wondered if your G4's memory was working correct? Try it the price of Rember 0.2.2b (freeware) is right. Thanks to the team at Kelly Computing. Dick