Mac Pro - Memory Question

[ikarus79m]

Hey guys,

I just ordered a Mac Pro with 4x512 MB (2gig) from apple and would like to upgrade 1-2 more Gigabites over the next few weeks. I am wondering if I have to continue to buy 512MB modules, or if I can mix my existing 512MB modules with 1gig or even a single 2gig module. Does this work? Does it affect performance?

I am also looking at third party ram, in particular from DealRam. http://dealnews.com/memory/prices/systems/Apple-Mac-Pro-/44047/1GB.html

It says that it is Mac Pro certified and is pretty cheap. Any comments?

 

[Sun Baked]

Must be added in pairs ...

Mac Pro Memory (FB-DIMM) DIY Replacement Instructions (pdf)

An yes, anything other 4x??GB/MB arrangement will affect performace, since the machine is capable of quad channel operation using 4 matched DIMMs split between Riser A & B.

But more memory will trump the loss of perfomace caused by falling back to dual channel operation.

 

[ikarus79m]

So if I understand that document correctly, that means that in addition to the 2 pairs of 512MB in my 2GB configuration, I could add an aditional pair of 1GB modules to bring up my total to 4GB correct?

As long as I always install in pairs the same size and manufacturer I am fine correct? (Meaning I don't have to install only 512MB modules just because my first two pairs are 512 modules.)

 

[robbieduncan]

You can install 2x1Gb (or even 2x2Gb) modules into the spare slots it you want. It's (marginally) faster to access the first pair of slots on each riser than the second pair so if you are doing this put the larger modules in the first slots as they will probably be accessed more (as they will be at the bottom of the memory space). This will minimise the amount of slower RAM.

 

[ikarus79m]

Thank you guys, that's very helpful. Now, has anyone ever heard of these people? The ram there seems VERY reasonable priced.

http://dealnews.com/memory/prices/systems/Apple-Mac-Pro-/44047/1GB.html