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Demo: Upgrading the RAM in the 2019 Mac Pro After Purchase

@MacRumors: Why purchase 8 sticks of RAM and not 6 or 12?
Won't this mean that the computer is 'only' running in quad channel (instead of hex channel)?
Unless 512GB RAM is really needed, wouldn't 6*64 GB (384GB) actually provide better performance?
 
Spectrum said:
@MacRumors: Why purchase 8 sticks of RAM and not 6 or 12?
Won't this mean that the computer is 'only' running in quad channel (instead of hex channel)?
Unless 512GB RAM is really needed, wouldn't 6*64 GB (384GB) actually provide better performance?
Click to expand...
Yes, as you say it would be running in quad channel, so max memory bandwidth will be about two-thirds (at best) of what the optimal six channel config would provide. Especially if you’re workload is constrained by memory bandwidth, but probably even if it isn’t, you would want to utilize all six channels. As you mention, 6 or 12 DIMMs would offer the best performance. Certain unbalanced configs could drop memory bandwidth to less than 17% of that attainable with 6 or 12 sockets correctly populated.

Lenovo offers a fairly comprehensive reference document on this subject:

 
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mytdave said:
  1. Apple historically rapes everyone on RAM prices. Theirs is not special. They use the same chips as everyone else - SKHynix, Elpida, Micron, etc.
  2. Apple SSDs are upgradeable, but tied to that obnoxious T2 chip. However, you can install insane amounts of SSD storage via PCIe slots, and even spinning hard drives with a mounting kit attaching to the internal SATA ports, or externally via Thunderbolt.
  3. The Mac Pro supports 6-channel RAM. This is a function of Intel's Xeon CPUs. That's why when we buy RAM for our workstations (which happen to be Dell because Apple wasn't making any previously) we do things like buy 6 sticks of 32GB instead of 4 sticks of 64GB. The amount is close, and the performance is better. This is not really a mystery, just Google it to learn more.
Click to expand...


Since it comes with 32GB RAM (RDIMM)

Can I add 2 sticks of 32GB RAM (RDIMM) each to get 96 or, is it unwise to mix 32GB sticks with the 8GB sticks it comes stock with?
 
casperes1996 said:
Well it would mean that you'd have 48GB running in hex channel and the remaining 48 only running in dual channel
Click to expand...


Good point- I will likely just get the 6x16 and hold on to the 4x8 as $100 from OWC is not worth it - might as well hold on to it in case of emergency
 
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