RAM in quad: want 8gb (2gbx4) from crucial?


macrumors 68000
Original poster
Aug 15, 2002

I bought an '09 mac pro quad, and went to crucial and trusted their 'maxed out option' for getting 6bg of RAM...


I understand that there are four slots, and that even though 6gb of ram is somehow ideal for the new processors, that a full 8 gigs would be of greater benifit in general.

Two questions:
-is this true?
-WHERE DO I BUY ANOTHER 2GB STICK THAT MATCHES THE RAM I BOUGHT FROM CRUCIAL? I can't seem to find on their website the ability to buy just one 2gb stick of this type!




macrumors 68020
May 21, 2009
Munich, Germany
The quad MP4,1 supports a maximum of 32 GB RAM at reduced bandwidth(4 x 8GB RDIMM).

At max bandwidth you can still run 24 GB RAM (3 x 8GB RDIMM or 2 x 8GB RDIMM + 2 x 4GB RDIMM)

All those options involving 8 GB sticks are fairly expensive at the time.

If you stay with UDIMMs 4 GB sticks would give you bigger capacity than you currently have.

Filling the fourth slot with an identical stick will always reduce your bandwidth but you are unlikely to ever use it anyway. So in reality it isn't much of a problem. A good compromise is using half size DIMMs on 3rd and 4th slot.

Never mix RDIMM and UDIMM! That will disable the memory.
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