Upgrading RAM memory

additionally, if you want to add RAM to speed up your Mac Pro, you may want to determine if the Mac Pro is HDD based or SSD based. if it is HDD based, you will get far more performance by upgrading to an SSD as compared to a RAM upgrade.

The Mac Pro 5,1 uses ECC RAM memory. You must be certain you are upgrading with the correct modules, there are a lot of different one that seem similar.

OWC sells RAM that :

works in your Mac,

or your money Back.

You may upgrade by the EACH DIMM. The optimum setup use three very-similar DIMMs, but do not dwell on that idea. The speedup from having ENOUGH RAM completely swamps the maybe five percent from matched DIMMS. Since the addressing for the Third and Fourth DIMM slots is shared, there are times (at the extremes) when the fourth slot can not be made to work reliably at top speeds.

There is another important stumbling block. DIMMs 16 GB and above have so many devices on them, they could not be made to work in the traditional way, by just connecting all the chip outputs together. To make them work, the DIMM needed an added Register to re-drive those outputs onto the memory Bus. Thai means that smaller and larger DIMMs can NOT be mixed on the same side.

For me, the best way forward recently was to buy TWO 16GB Registered DIMMs, and set all the old ones aside. That gave me optional expansion (by adding the third DIMM, and possibly the fourth) later.

when the price for one larger DIMM is lower than the price of two smaller DIMMs that add up to the same size, it is always better to go with the higher capacity DIMMs, because that saves you money immediately and leaves more room for expansion.

please see OWC Memory Upgrades For Mac Pro (2010 & 2012). they are well known to supply RAM that will work in your Mac.