What is my best option for RAM to upgrade a Predator PO5-640 (Processor 12th Gen Intel(R) Core(TM))

Download and install CPU-z, run it and find out the specifications of current RAM modules in the PC, also check the frequency of the modules installed in your PC, if they have JEDEC profile, you need to buy memory with JEDEC profile with same frequency as your current modules, if you have memory with XMP profile, you can buy memory with XMP profile with same frequency as your current modules.

CPU-Z | Softwares | CPUID

StevenGen

https://community.acer.com/en/discussion/679581/what-is-my-best-option-for-ram-to-upgrade-a-predator-po5-640-processor-12th-gen-intel-r-core-tm

The PO5-640 desktop can ONLY operate on max 64GB 4x 16GB DDR5-4400 MHz SDRAM 288-pin DIMM type ram, all the ram modules that you have listed above will all run at speed: 4400MHz if fitted to your desktop. Best is to match your oem 32GB 2x 16 DDR5 ram that you have exactly. This is clearly outlined in the PO5-640 PDF manual (see below) that shows users exactly how to populate the ram DIMMs slots. Install CPUz and look at your exiting ram specs and match that exactly as then you will have your desktop running at DDR5-4400MHz speed memory.

If you have 32GB of ram at 2x 16GB in DIMMs 1 & 2 you can NOT put a 1x 32GB module (you can't use 32GB ram modules) into any DIMM slot to raise the ram total to 64GB, you need to upgrade with 2x 16GB DDR5-4400MHz type ram as shown below 1 to 4 DIMMs slots have to be populated with 4x 16GB DDR5-4400MHz (or match your existing 32GB 2x 16GB in DIMMs 1& 2) for your PO5-640 desktop with standard ram and not overclocked XMP type ram.