Question Best RAM capacity / frequency for working with i9 13900KS?

[MoeNAGY23]

** Please note, my knowledge with memory is very limited, hope I can back simplified answers!

Hi all, I'm getting a new build soon and I'm going with i9 13900KS on it with RTX 4090 on ASUS ROG MAXIMUS Z790 HERO DDR5.

I know, many won't advice with overclocking the 13900KS but what if I want to be an overclocking freak and do it ?? I'd aim to try to overclock the CPU ONLY, not overclocking RAM at all beyond enabling XMP.

My question here is what RAM capacity / frequency should I be using the the 13900KS? My motherboard is advertised to support up to 7800mhz.

32GB sticks of DOMINATOR® PLATINUM RGB 32GB (2x16GB) DDR5 DRAM 7200MHz C34
OR
64GB sticks of DOMINATOR® PLATINUM RGB 64GB (2x32GB) DDR5 DRAM 6000MHz C40

• Does 64GB result in better CPU clocking over 32GB ?
• Why are people advising me to use only 2 sticks of RAM? So, if I wanted to use 4X16GB 7200MHz C34 module listed above for 64GB, what's the downside to that?

 

[DRagor]

Does 64GB result in better CPU clocking over 32GB ?

No difference. RAM speed has nothing to do how much you can OC CPU. That said, if you pair up fast CPU with slow RAM you may encounter situations where CPU will have to 'wait' for RAM effectively negating some of its speed. Also, amount of RAM is dictated by your use case. Gaming etc - 32 GB is plenty, but if you do things like graphics processing the more RAM the better (and it may even be better to have more slow RAM then less fast RAM).

Why are people advising me to use only 2 sticks of RAM?

Because DDR5 boards have problems with running 4 sticks - typically they will run at much lower speed then what RAM is capable. It may be already sorted out on some boards (and certainly will be in future) but for now sticking to just 2 sticks is safer approach.

 

[alceryes]

Because DDR5 boards have problems with running 4 sticks - typically they will run at much lower speed then what RAM is capable. It may be already sorted out on some boards (and certainly will be in future) but for now sticking to just 2 sticks is safer approach.

Not just with DDR5, but any CPUs with IMCs are stressed more the more memory slots you populate. This usually manifests in having to run 4 sticks at slower clock speeds or looser timings than 2 sticks.
Unless absolutely needed, just go with 2 sticks of RAM of the appropriate speed and size.