Memory arrangement help?

[babbler]

I have a 4-core Mac pro approx. 6 months old.

It was bought with 2Gb RAM. This was arranged with 2 x 512 on each memory card. The RAM on the upper card has failed. As a temporary fix I moved the 2 x 512 from the lower card to the upper so that it ran OK with 1Gb.

The original supplier has now replaced the 2 x 512 which failed with 1 x 1Gb, He says I should add this to the top card. This would leave 2Gb on the top and nothing on the lower card. This does not seem right. I read somewhere that you should spread RAM between the cards to maximise the processor efficiency.

What should I do ?


Thanks

 

[Sean Dempsey]

I have a 4-core Mac pro approx. 6 months old.

It was bought with 2Gb RAM. This was arranged with 2 x 512 on each memory card. The RAM on the upper card has failed. As a temporary fix I moved the 2 x 512 from the lower card to the upper so that it ran OK with 1Gb.

The original supplier has now replaced the 2 x 512 which failed with 1 x 1Gb, He says I should add this to the top card. This would leave 2Gb on the top and nothing on the lower card. This does not seem right. I read somewhere that you should spread RAM between the cards to maximise the processor efficiency.

What should I do ?


Thanks

I don't think a Mac Pro can have an odd-number of ram chips.

And, you should balance them between the cards.

 

[CanadaRAM]

Not quite --

RAM must be installed in pairs - if you have 2 RAM modules (2 x 1 Gb) the put them in Riser A slot 1, Riser A slot 2 -- do NOT balance them between the 2 risers.

If you have 4 RAM modules, put them in A1 A2 B1 B2

I think what Sean meant to say was if you have 4 identical RAM modules, then putting them in the corresponding slot pairs in both risers - A1 A2 B1 B2 - gets you a very small speed improvement from 256 bit access.

MR Guide to Understanding Intel Mac RAM