Resolved SOLVED: "4x2Gb + 3x8Gb" or "8x4Gb" RAM? (MacPro 2,1)

[Electronic1982]

UPDATE: Problem Solved: I could go up to a max of 16Gb with 8x2Gb dimms, and a max of OSX 10.7.5


Hi all, I have a Mac Pro running Leopard 10.5.4 (bought on 27th Sept 2007 - MacPro 2,1 - 2 Quad-Core Intel Xeon 5400 Series) with 8 slots avaliable for 667MHz DDR2 ECC FB-DIMM Memory sticks and I want to upgrade to 32Gb RAM. (I'll also be upgrading to the latest OSX as well)

I current have 9Gb RAM installed like this:

SLOT 1: 2Gb
SLOT 2: 2Gb
SLOT 3: 2Gb
SLOT 4: 2Gb
SLOT 5: 512Mb
SLOT 6: 512Mb
SLOT 7: -empty-
SLOT 8: -empty-

TOTAL: 9Gb RAM

The question is, which of the a) or b) suggestions below would be better for optimal performance, stability and less strain on the Motherboard? (Price is not an issue)

a) (2Gb and 8Gb mix)

SLOT 1: 2Gb
SLOT 2: 2Gb
SLOT 3: 2Gb
SLOT 4: 2Gb
SLOT 5: 8Gb
SLOT 6: 8Gb
SLOT 7: 8Gb
SLOT 8: -empty-

TOTAL: 32Gb RAM


b) (all slots to have 4Gb each)

SLOT 1: 4Gb
SLOT 2: 4Gb
SLOT 3: 4Gb
SLOT 4: 4Gb
SLOT 5: 4Gb
SLOT 6: 4Gb
SLOT 7: 4Gb
SLOT 8: 4Gb

TOTAL: 32Gb RAM

Any suggestions or any other view points welcome. Does it even make a difference? Thanks all.

 

[Electronic1982]

bumping for opinions.

 

[Umbongo]

You can't do the first one, so the second one.

They have to be in pairs and you can't use 8GB DIMMs.

 

[OS6-OSX]

Also, if you are using 667mhz ram sounds like a 1,1.
You should read on this forum what is the "latest" OSX that can be used or how they "made" it work

 

[Electronic1982]

Also, if you are using 667mhz ram sounds like a 1,1.
You should read on this forum what is the "latest" OSX that can be used or how they "made" it work

I've done some searching and it seems that I can go 32Gb with a full set of 4Gb DIMM's. But there's just 1 last question:

I plan to upgrade to latest OSX. I have a 64-bit computer running OSX Leopard 10.5.4 (bought on 27th Sept 2007 - MacPro 2,1), will these 667mhz DIMM's run on the lastest OSX? if not, then what is the lastest OSX I can upgrade to?

UPDATE: Problem Solved: I could go up to a max of 16Gb with 8x2Gb dimms, and a max of OSX 10.7.5.