Question Need RAM advice for new gaming PC setup


May 26, 2019
I plan to build a new gaming PC either at the end of this year or early next year using an AMD Ryzen 5900X CPU and either an AMD RX 6800 XT or 6900 XT or Nvidia RTX 3070 or 3080 graphics card. My intention is to use this PC for both gaming at 1440p or possibly 4K (if I find a good deal on a 4K gaming capable monitor) and some 1080p and 4K video editing (not Hollywood level video editing). Now I am not super knowledgeable in all aspects of RAM properties and specs so I hope I can get some good recommendations. My understanding is that for CAS Latency or whatever you call that property that has the #-#-#-#, the lower the number, the faster the process speed. The CPU memory speed for the Ryzen 5900X is listed as 3200 MHz and my understanding is that I should go with RAM sticks that have a higher memory speed than the CPU. Lastly, my understanding is that the more the RAM, the faster processes are carried out (64 GB vs 32 GB). My question is what are your recommendations on memory specifications like the ones I mentioned and any other important specifications and how much memory do you recommend that I go for? I am trying to stick around the point where the price-to-performance balance maxes out and avoid going either cheap or overkill. I also do not plan to overclock.



Retired Mod
The motherboard chipset is going to dictate what memory speed you can run, and how much you can run. The specs for CPU memory support are ONLY for the native memory speed support. They have nothing to do with the actual supported maximum memory speed.

So far for Ryzen 3000 series (And most probably, from what we can tell so far, the 5000 series as well) the maximum sensible memory speed is going to be 3600mhz regardless of other considerations. Either a 3200mhz CL14 kit or a 3600mhz CL16 kit, both of which have about the same true latency and therefore are pretty closely matched in pure memory speed performance, are optimal. Some few configurations might be able to run faster memory kits without paying a latency penalty by increasing the infinity fabric from a 1:1 ratio to a 2:1 ratio, but those types of configurations are not typically for the average system. A really great CPU sample along with a very high end motherboard would probably be necessary to even start thinking about going above 3600mhz at all.

For most, you also want to stick to a TWO DIMM kit. While there is some evidence that perhaps there might be some small gains to had using a 4 DIMM single rank kit, or 2 DIMM dual rank kit, it is probably not enough for the average person to want to worry about AND more importantly, many Ryzen platforms will NOT run at XMP profile speeds above 3200mhz (2933mhz for some) with more than two DIMMs installed.

Your idea that having more RAM means "the faster the processes are carried out" is unfortunately not quite accurate. IF you NEED more than 16GB, or more than 32GB, etc., then having more will result in better performance. If however you don't actually USE enough memory to NEED that quantity, then having more is not going to increase performance at all in 99% of cases. If you are hitting between 14-16GB of usage, then having 32GB is probably helpful. If you are hitting at less than that, then having more isn't going to do ANYTHING for you. If you THINK you might NEED that additional amount LATER, then get it NOW, in ONE kit. Don't buy memory with the idea that you can just "add" more later, because once you are past the JEDEC natively supported specifications, chiefly 2666mhz for the majority of systems, 3200mhz on some newer systems, you will increasingly run into potential problems of adding memory to an existing kit not wanting to "play nice" with the first kit. That holds true even when they are the exact same model number as seen, and further explained, here: