Memory question

[bbplayer5]

I have 4 gigs of ram in my Mac Pro, and took out the 2x512 chips it came with. So I have 4x1 GB chips in the machine. I cant put in the other 2x512 chips right? You cant really mix and match chip sizes can you?

If so, which slots would I put them in?

 

[robbieduncan]

RAM must be installed in matched pairs (so 2x1Gb is a pair as is 2x521Mb) but individual pair do not have to be matched to each other so you can mix 2x1Gb and 2x512Mb freely.

The first pair of slots on each riser can be accessed by the system very slightly faster than the second pair (as they are daisy chained off the first) so I'd put the largest sticks in the first slots.

 

[bbplayer5]

But I would put 1 of the 512 chips on each riser right? I have 4 x 1 gig chips in the first 2 slots of each riser making it quad channel (if i have that right). So id put one 512 in slot 3 on each riser?

 

[robbieduncan]

But I would put 1 of the 512 chips on each riser right? I have 4 x 1 gig chips in the first 2 slots of each riser making it quad channel (if i have that right). So id put one 512 in slot 3 on each riser?

No that won't work. You must install them in pairs in the risers. So you would have to put the 512s in 3&4 on riser 1

 

[Schroedinger]

This might help you visualize what's going on:

http://developer.apple.com/document...l/HWTech_RAM/Articles/RAM_implementation.html