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Caligator

macrumors newbie
Original poster
Mar 13, 2022
21
1
I'm experiencing slow performance and wondering if my RAM configuration is slowing my Mac Pro mid 2012 5.1, 3.2 GHz Quad-Core Xeon. Running Big Sur 11.7.1 with Opencore. I have 48 GB 1066 DDR3 ram, 2 x 16; 2 x 8 set up. Here's a pic of the config. How should I configure for max performance? Thanks.

CleanShot 2023-03-15 at 03.57.36.jpg
 

rm5

macrumors 68040
Mar 4, 2022
3,036
3,505
United States
Generally, these Nehalem/Westmere Xeons run best in triple-channel memory configurations. I run 32 GB in mine (4x 8 GB DIMMs), but obviously since it's 4x 8 GB sticks, it's actually not running in triple-channel.

EXAMPLES of triple-channel configurations for single/dual CPU tray 5,1s:
  • Single CPU with 3x 8 GB sticks (24 GB)
  • Single CPU with 3x 16 GB sticks (48 GB)
  • Dual CPU with 6x 8 GB sticks (48 GB)
  • Dual CPU with 6x 16 GB sticks (96 GB)
Obviously you could go with 4 GB sticks, too if you wanted a small amount of RAM. Whereas you could theoretically do the following with all your RAM slots:
  • Single CPU with 4x 8 GB sticks (32 GB) - this is how I have mine configured
  • Single CPU with 4x 16 GB sticks (64 GB)
  • Dual CPU with 8x 8 GB (64 GB)
  • Dual CPU with 8x 16 GB (128 GB)
Obviously other configurations exist, but these are just the easiest examples to show. But these above configurations are NOT triple-channel because you'd be saturating all of the DIMM slots.

So to answer your question—try running either 3x 16 GB or 3x 8 GB (for 48 or 24 GB respectively), and see how it works. I should actually test that out myself, too!

EDIT: I noticed your RAM is running at 1066 MHz, so it would be advantageous for you to upgrade to a Westmere CPU so that (provided your DIMMs are 1333 MHz), you could run them at their full 1333 MHz. Plus, I noticed my system was running much snappier after I upgraded from the Nehalem garbage to a Westmere CPU (see signature).

EDIT #2: attached About This Mac screenshot
Screen Shot 2023-03-15 at 1.18.52 PM.png
 
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