Question DDR 4 (32 GB) Two or Four Sticks?

[HC1Gunner]

I'm building a new Ryzen 9 3900 XT based PC, and I have purchased the Gigabyte X570 AORUS Master. I want to run a total of 32GB of RAM. Is it better to run (2) dimms of 16GB, or (4) dimms of 8GB? I'm sure there are some pros and cons to both sides of the fence, but I can buy b die g-skill (4 x 8GB) @ 3600 (PC4 28800) Timing 14-15-15-35, vs (2 x 16GB) DDR4 3600 (PC4 28800) Timing 16-16-16-36 CAS Latency 16. The two stick kit latency is quite a bit higher.

 

[damian101]

Having more ranks per channel can increase performance to a certain degree. Going from 1 to 2 and going from 2 to 4 ranks per channel both showed to have some performance improvement on the Ryzen platform. But having more ranks also increases the load on the memory controller, reducing the achievable maximum RAM frequency. Having those ranks spread out over more memory modules increases the load on the memory controller even more. 3600 MHz will most likely be reachable even with 4 dual rank modules on your setup, but only these frequencies are officially supported for Zen2:

I personally would go with two DIMMs. Assuming those G.Skill 16GB modules are the F4-3600C16D-32GTZ both options should use Samsung B-Dies, so the choice is between 4 single rank modules with slightly higher timings and 2 dual rank modules with slightly lower timings. Two DIMMs leaves room for an upgrade and 16GB modules are also generally easier to sell on the used market. But unless you want to overclock your RAM beyond 3600 MHz or tighten the timings manually you will get slightly better performance with the 4x8GB kit. Assuming that your memory controller can achieve 3600 MHz with four single-rank modules, which is most likely the case.