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high heaven

Suspended
Original poster
Dec 7, 2017
522
232
I have 32gb of RAM but it's difficult to work with. I'm planning to buy more RAMs but I'm not able to find a same RAM from ebay. I wonder if I can just get any kind of 1333mhz ECC RAM for Mac Pro?
 

h9826790

macrumors P6
Apr 3, 2014
16,656
8,587
Hong Kong
There are 2 main specs you have to focus on.

1) You CANNOT mix UDIMM with RDIMM. So, let's say all your current RAM are UDIMM, you must buy UDIMM. If you mix UDIMM and RDIMM together, your cMP won't boot.

2) You should buy 2Rx4 (AKA dual Rank) memory, the cMP can work with other memory rank (e.g. 4Rx4), but that often cause other issues.

Apart from that, you can pretty much install whatever DDR3 you want onto the cMP.

You can mix ECC with non ECC, 1333MHz with 1066MHz, or 4GB DIMM with 8GB DIMM. The cMP will work just fine with all that.
 

high heaven

Suspended
Original poster
Dec 7, 2017
522
232
There are 2 main specs you have to focus on.

1) You CANNOT mix UDIMM with RDIMM. So, let's say all your current RAM are UDIMM, you must buy UDIMM. If you mix UDIMM and RDIMM together, your cMP won't boot.

2) You should buy 2Rx4 (AKA dual Rank) memory, the cMP can work with other memory rank (e.g. 4Rx4), but that often cause other issues.

Apart from that, you can pretty much install whatever DDR3 you want onto the cMP.

You can mix ECC with non ECC, 1333MHz with 1066MHz, or 4GB DIMM with 8GB DIMM. The cMP will work just fine with all that.


IMG_0709.jpg

This is mine and will that RAM work with this?
 

flowrider

macrumors 604
Nov 23, 2012
7,323
3,003
^^^^RAM speed in the cMP 5,1 is determined by:

1. The CPU

2. The rated speed of the slowest module installed.

Lou
 

JedNZ

macrumors 6502a
Dec 6, 2015
647
247
Deep South
I’m looking at two IBM ram sticks on a local auction site. I can’t tell if they’re U- or RDIMM. Can anyone confirm which one they are from the labels, and if they would work in my cMP (see
 

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h9826790

macrumors P6
Apr 3, 2014
16,656
8,587
Hong Kong
But the cMP will work with the lower speed right?
In that case, all RAM will work at 1066MHz
[automerge]1590819385[/automerge]

View attachment 919810
This is mine and will that RAM work with this?
Should work
 
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