4x512MB - adding 2x1GB: What is the best configuration?

[milozauckerman]

maybe a better question is what is better: 4x1gb or 8x512mb which would fill all the slots. Anyone?

4x1GB (or 4x2GB). Fewer DIMMs = lower latency.

 

[foxymoron]

Still not gettting it!

So, I understand there are 4 risers. I understand that the optimum is 4 gb. I understand that Apple ships with 1 gb as two 512 sticks. Those are in one riser or two? Can I buy 3 gb of 1 gb put them in three risers and use the two 512 sticks in the remaining riser or do they absolutely have to all be 1 gb? What would be the best thing to do with the 512 mb sticks after that. Go ahead, be as creative as you like.

FM

 

[robbieduncan]

So, I understand there are 4 risers. I understand that the optimum is 4 gb. I understand that Apple ships with 1 gb as two 512 sticks. Those are in one riser or two? Can I buy 3 gb of 1 gb put them in three risers and use the two 512 sticks in the remaining riser or do they absolutely have to all be 1 gb? What would be the best thing to do with the 512 mb sticks after that. Go ahead, be as creative as you like.

FM

There are two risers not 4. Each riser has 2 channels going to it and RAM must be available in both channels for it to works (so you have to add RAM in pairs). Each riser has 4 slots on it allowing for a total of 4 pairs of RAM to be added. Only the first two slots on each riser have a direct connection to the chipset so the RAM in the second pair on each riser will be higher latency (i.e. there will be a longer delay when the chipset needs to talk to it) as it is accessed via the first pair of RAM.

Therefore an optimum setup is to have the first pair of slots filled on each Riser and not have anything in the second pairs. The chipset works at it's fastest if both risers have the same RAM configuration on them. So if you want 4Gb the optimal setup is 4x1Gb in the first two pairs of slots on each riser.