Hi John, Is the RAM seated firmly? Sometimes it takes a surprising amount of force to get it fully down in its socket. It should 'click', kind of. Go to Versiontracker.com There are downloadable utilities with names like 'Ramtester' you can search for that can diagnose your RAM. Have you looked at your Profiler, Hardware tab to see how the computer identifies your RAM (if at all) and how that matches up to your other stick. Macs can be very finicky about RAM that's not fully in spec with all machine requirements. They can tolerate lower speed sticks - like 222 v. 333 - but will run at the lower speed. But OWC should have sent you the right stuff to begin with. They have an excellent reputation for quality and customer service. Good luck, jon Original Message: ----------------- From: Patrick J. Runcie macandlinuxuser at gmail.com Date: Mon, 4 Feb 2008 20:30:40 -0500 To: g4 at listserver.themacintoshguy.com Subject: RE: [G4] memory problem in dual 867 The ram you purchased, you need to find out if it's high or low density vs the ram that the computer you have is limited to low or will accept high density ram. It's possible, that you may have purchased a high density stick & the computer will only accept low density. Another suggestion is, it's possible the stick is bad. Try it out on another computer, even a Windows system. That will rule out if the stick is bad. -----Original Message----- From: g4-bounces at listserver.themacintoshguy.com [mailto:g4-bounces at listserver.themacintoshguy.com] On Behalf Of johnnyg Sent: Monday, February 04, 2008 8:04 PM To: G4 at listserver.themacintoshguy.com Subject: [G4] memory problem in dual 867 Hi, I just purchased from OWC a 512 memory chip to put into this newly acquired mirror doors with only one 512 slot taken......however, after installing the memory, I have had freezes kernel panics and other strange attrocities often. I moved the memory about in different slots and tried resetting the pram, and pma. No help so I removed the memory and everything is smooth once again. Is there some magic I should put into service here or do I likely have a bad memory chip? OSX10.39. Thanks. John _______________________________________________ G4 mailing list G4 at listserver.themacintoshguy.com http://listserver.themacintoshguy.com/mailman/listinfo/g4 _______________________________________________ G4 mailing list G4 at listserver.themacintoshguy.com http://listserver.themacintoshguy.com/mailman/listinfo/g4 -------------------------------------------------------------------- mail2web.com - Microsoft® Exchange solutions from a leading provider - http://link.mail2web.com/Business/Exchange