Ram problem

[showmehost]

I just got another 2gigs of ram for my 2.66 mac pro. bought it with the stock 1gb, added a matched pair (2x1gb) and now just added another matched pair (2X1gb). powered up and the computer only recognized the 1gig sticks (all four) but not the orig 2x512. i have placed the ram in the proper slots and made sure they were seated properly but About This Computer has DIMM riser A/DIMM 3 & 4 listed as empty. that is where my 2x512 sticks are. any ideas?

(the newest ram is being recognized, so that's no prob. my mac just "forgot" about the orig ram i guess)

thanks
JW Patterson
Auto Professionals LLC
Kansas City, MO.

 

[Makosuke]

First things to try would be:

What happens if you remove the RAM you just installed--do the 512s reappear?

What happens if you move the 512s to another pair of slots (say, swap with one of the other pairs)?

Those will point to whether it's a problem (coincidental?) with the RAM itself, with the slots, or with those sticks not liking to play nice with the new ones.