Memory Upgrade for my Mac Pro 2 x 3.2GHz Quad Core Intel Xeon to 18GB DDR2

Question

Memory Upgrade for my Mac Pro 2 x 3.2GHz Quad Core Intel Xeon to 18GB DDR2

Hi guys, I have been searching online for a few hours to find the best method of upgrading the memory on my Mac Pro.

There are differing opinions on what is best practice. Many sources claim that memory sticks have to be paired yet I ring Apple Technical Support today and they claim I can actually install the memory sticks in any order including odd numbers.

I currently have 2 x 1GB 800MHz DDR2 FB-DIMM sticks and have 8 slots in total i.e. 6 vacant

I want to install 4 x 4GB sticks and was wondering what the best method would be.

From what I read the best method would be to install 2 x 4GB sticks in slots 1 and 2 respectively on Riser 1 and 2 x 4GB sticks in slot 1 and 2 on Riser 2

This leaves me with 4 vacant slots and 2 x 1GB sticks which I would personally install in slots 3 and 4 on Riser 1

Is this correct?

Thanks in advance

Mac Pro, Mac OS X (10.5.8)

Posted on Nov 21, 2012 8:57 AM

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Answer 1

The hatter

Level 9

60,980 points

Nov 21, 2012 11:03 AM in response to Averroes Design Ltd

Well, 17% boost using 8 DIMMs.

So forget leaving 4 vacant.

4GB DIMMs are expensive.

667MHz works fine, 4% slower but then you would have 8 DIMMs, looks like gain of 12%+.

And 667MHz are cheap but still highest quality. 8x2GB would run $160 @ Amazon.

How To Install and Remove Memory Mac Pro

https://support.apple.com/kb/HT4433

2x2GB FBDIMM DDR2 667MHz @ $39

http://www.amazon.com/BUFFERED-PC2-5300-FB-DIMM-APPLE-Memory/dp/B002ORUUAC/

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Answer 2

Nov 22, 2012 1:29 AM in response to The hatter

Hi and thank you for your reply buddy,

Im not technically very savvy however I was under the impression my machine already comes with 800MHz sticks, that is what I would have to install.

Furthermore, assuming I was **** bent on wanting to install 800MHz sticks would adding 4 x 4GB sticks to the current 2 x 1GB sticks work fine and likewise, would I install them as mentioned in my first post?

In total I have 2 slots vacant as i have 4 x 4GB + 2 x 1GB

Cheers

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Answer 3

Nov 23, 2012 8:26 AM in response to Averroes Design Ltd

Any ideas on the above pls guys

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Answer 4

Nov 23, 2012 9:27 AM in response to Averroes Design Ltd

Which Mac Pro is it? I think early ones required matched pairs. But the newer ones don't.

Anyway, for me when I put in new RAM, the first thing that came up when I started was a message saying the RAM was not installed in the best way, then telling me how to do it for better performance.

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Answer 5

The hatter

Level 9

60,980 points

Nov 23, 2012 10:29 AM in response to Averroes Design Ltd

Barefeats: your system will accept and work with 667MHz at 4% reduction (for all the DIMMs obviously).

You do not need to have 800MHz and given the difference in price -

Did the fact that 8 DIMMs affects performance by 17% get missed too.

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Answer 6

Nov 23, 2012 1:25 PM in response to The hatter

My Mac Pro is an early 2008 with Intel Xeon

The hatter, your last point is which I was wanting a little more clarity on. Are you saying for example 16GB occupying 4 slots in the the form of 4 x 4GB sticks performs less than 16GB spread over 8 i.e. 8 x 2GB sticks

Furthermore, what if I did already have the 4GB sticks how would I carry out the aforementioned i.e. install 4 x 4GB sticks as well as the 2 x 1GB sticks that the machine already come with

Cheers and thank you so much for putting the effort in replying to me, I really do appreciate the help

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Answer 7

The hatter

Level 9

60,980 points

Nov 23, 2012 1:34 PM in response to Averroes Design Ltd

Just mix as long as they are paired (adjoin slots)

As I did not link but said, Barefeats did the tests - back in first half 2008.

4x1GB + 4x2GB

2x4GB + 6x2GB

2x4GB + 4x2GB + 2x1GB

Given $40 for 2x2GB makes it more affordable and worth it. Spend the difference on a fast or large hard drive.

http://www.barefeats.com/harper5.html

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Answer 8

Nov 23, 2012 1:52 PM in response to The hatter

The only reason I wanted 4GB sticks was so in future I could occupy 4 more slots with 16GB RAM extra incase I ever needed it (which I highly doubt but nonetheless)

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