Mac Pro Ram Pairing Question

[iranintoavan]

First off I know there are lots of RAM questions and that you will probably say "search!!!" Well I did and I couldn't find a clear answer so heres my quick and simple question.

I have the first revision of the mac pro and I have the stock 1 gig of ram (2x512). I am looking at getting either 2(2x1gig) or 4(2x2gig) from OWC. Now I know that you have to buy in pairs for max speed (if that's the right term). Does this mean I would be fine having in one ram riser 2 pairs of different sizes such as (2x512mb) and (2x2gig)? Thanks for all the help.

 

[CanadaRAM]

Have a look in the MR Guide to Installing RAM

It's fine to have a pair of one size alongside a pair of another size. The gains from 256 bit access (by installing 4 identical) are minimal.

 

[swingline]

I kind of have the same question but I've already installed 2x1gb ram along with the stock 2x512 ram. It feels pretty slow and the boot up time sucks.

 

[CanadaRAM]

Well, if you installed it per Apple's diagram, your slowness is not due to the extra RAM -- unless you have some defective RAM... What are the Recoverable ECC errors standing at in Activity Monitor?

 

[iranintoavan]

Have a look in the MR Guide to Installing RAM

It's fine to have a pair of one size alongside a pair of another size. The gains from 256 bit access (by installing 4 identical) are minimal.

Ok so let me get this right. At the moment I have (2x512) in A1, A2. If I ordered 4gigs (2x2gig). I should re-arrange it to be, (2x2gig) in A1, A2 then the old (2x512) in B1, B2?

Thanks for giving me that link and helping!

 

[CanadaRAM]

Yes.

Theoretically, there should be no difference between A1 A2 and B1 B2, but it's just easier to remember - start with your largest RAM in A1 A2 and work your way from there.

 

[iranintoavan]

Thank you very much, that cleared everything up!

 

[KeithBrofsky]

Mixed Combo & What's the Max?

Hi Mac Friends,

I have a question... leave it me to complicate things!

I run a Mac Pro, Early 2009 quad core with 2x 2.93 GHz.

I had 6 sticks of RAM at 1 gig each. I do pro photography and now video, and its been bogging down. Time for RAM.

I thought I read that 16 gigs is all it can handle (?) so I bought 3 sticks of 4 Gigs each, and kept 5 of the 1 gig sticks. I put them in order as recommended on the handy popup guide. Its running better, but I wonder if I shouldn't have another 4 gig stick to match the Mis-paired duo (4 & 1).

4. 1
4. 4
1. 1
1. 1

Also, I bought a 2 Tb hard drive and wondered if I should make it my primary starter disc, or make it a scratch disc instead. Its worth noting I use a 1 Tb drive as my Time Machine, but I can't use TM for all the photo files. Those are on a Drobo with 8.8 TB installed.

Thanks so much for your knowledge and kindness in sharing it in kind.

Keith

 

[bsbeamer]

I run a Mac Pro, Early 2009 quad core with 2x 2.93 GHz.

Believe max RAM for that machine per is 16GB x 6 (six sticks of 16GB RAM) for a total of 96GB. If wanting to use all available slots, you can go 8GB x 8 (eight sticks of 8GB RAM) for a total of 64GB.

Not sure what I'd recommend with the mix & match system you have going. I've had had issues with pre-2010 machines and mixing RAM sets.