Hello Mac gurus, I purchased a 20" iMac G5, and I've had it for about a month. I ordered it from a particular online retailer, which shall remain nameless, other than to say it could be considered a virtual Mall for Macs or PCs. Anyway, I ordered a 20" BTO which included one 512 MB RAM chip from Apple, and the built-in Bluetooth. This online retailer has a promotion where they put in an extra 256 MB RAM "free", but you pay $39.99 for installation. (I originally had an order for the same set-up through Apple, but this way, I saved sales tax and shipping.) When I received my computer, I opened it up, plugged it in, got all excited and flustered, and upon start up, as in the grey apple just before the spinning circle thing, the screen goes dark, and it crashes. I couldn't even start up the computer without yanking the extra chip. After I took it out, everything was fine. So I sent it to the manufacturer and I just got the replacement chip. I put that in, and the computer still crashes. My main question is, has anyone heard of a computer having problems when both RAM slots are filled? I put the Apple chip in the other slot, and everything works fine, so I don't think it's either slot itself. The computer recognizes the memory in About This Mac... when it's in there, but the computer crashes all over the place with the extra chip in. I'm just not sure if I should be taking my iMac to Apple to check out, or if this memory just sucks. (I realize it's like $30 worth of RAM, and you get what you pay for.) Thanks everyone for your thoughts. I'm at work right now, but when I get home, I'll post the details of the chip if that would help.