Just installed two 2 gb chips to add to the existing 2gb that's already in the machine. The new ram isn't showing up. Is there a procedure for the tower to recognize these new items? Thanks.
I'm assuming it's a new Mac Pro 8-core? If so, you need to do it in pairs. So you had one chip each on the upper and lower card. Move one chip to the next slot in the bottom card and put the new chips in the original and second slot on the top card.