MP 1,1-5,1 Upgrading RAM in 5.1 cMP

[macaddress]

32GB DIMMs are not supported by macOS, you need OpenCore to make it supported and the config is complex/manual.

When MacPro4,1 was designed back in 2008ish, the usual DIMM was 1GB, with 2GB options, 4GB DIMMs were insanely expensive. Back then made sense to have a 4th slot sharing the 3rd channel to have more memory installed, even if it was slower.

3Rx4 is an unusual type of DIMM that started to be supported with some blade servers with IvyBridgeV2 Processors, no Mac ever used one.

Ahh I see I just found it noticed they were booted into windows to get that result.

going to experiment with the 4rx4 and see how it reacts if i remove the 4 and 8 slot vs, the 2rx4.
(Note something is messed up with my system, i have no recovery due to following martins monterey guide)

Edit: Well how about that..? 4rx4 slots 1,2,3. - 5,6,7.
I assume I'm better off with the 2rx4? be a hot minute before I benchmark them

 

[macaddress]

MacPro5,1 was designed to work with dual rank DIMMs (2Rx4).

Just did testing, i need to break down more of blackmagics Braw more in depth so ignore that. but this was quick go.
Obviously 4Rx4 @800mhz 128 performed the worst. However, at 96gb 1066mhz is identical to 2Rx4.