Which memory upgrade for my 2008 Mac Pro?

[hermanthekid]

I just bought my first Mac, an 8-core 2.8 GHz Mac Pro, and I am looking to upgrade the RAM from the stock 2GB to 8GB. I think I remember reading that you get the best performance when you fiill all of the memory slots as opposed to just filling 1/2 of them. Is this correct? I thought you just had to install DDR2 memory in matched pairs. Is there an unlocked performance boost when all available slots are filled?

I don't forsee myself ever needing 32GB of RAM before I would sell this machine and move on to another, but I can see myself putting 16GB in it. What would be the better upgrade, installing 4 x 2GB modules or 2 x 4 GB modules? With the former I would eventually fill all of the available slots for less $ whereas the latter option would leave open the possibility of putting 32GB in it and maybe be better for resale 5-6 years down the road due to the expansion opportunity.

Am I overthinking this in trying to plan for the unknown?

 

[bozz2006]

yes.

but it here

You need the 800MHz variety of DDR2 FB-DIMMS with the huge heatsinks. from what i understand, with 8 modules you deal with latency. from what i understand, 4 modules is the ideal. from what i understand, the performance increase from utilizing quad channel, and the performance hit from having 8 modules may be negligible to the point where they are imperceptible to the user.

 

[Umbongo]

I'm pretty sure adding 4x2GB to your existing 2x1GB will give you the best overall performance. You probably wouldn't notice the difference anyway.

 

[hermanthekid]

I was going to trade in the 2x1GB modules to OWC for the rebate. Is that not a good deal? Looks like they give you ~50% of their sale price. I guess I could always sell them myself at a later date if I needed to replace the with more dense modules.

Thanks for your input.

 

[bozz2006]

I always keep my old RAM. Mainly for trouble-shooting in diagnosing problems later. The money they give you back never seems worth it to me.