I have i7 12700K, 32 Gb RAM @3200MHz along with RTX 3070 running 1440p. I do get limited by main thread and recently discovered the RAM was speed limited by default BIOS configuration. When I changed it to have the RAM run at 3200MHz, I got an instant boost of 10+ FPS.
This leads me thinking - will increasing the RAM to 64 Gb have any uplift? Looking for advice.
No. MSFS doesn’t need any more RAM than you already have.
64GB would only benefit you if you use a RAM drive. I created one for my Rolling Cache. Much faster than a disk-based cache.
Also, some people have reported that XMP won’t work well with 4 sticks of RAM. I went from 2x16GB DDR4-3600 to 4x16GB of the same and haven’t had any issues with tested RAM speed/latency.
Yes 4 DDR5 sticks are problematic with many 790 boards, even if the sticks are on the QVL.
For example, my 128Gb is 4x32GB rated at 5200 and must be run at 4000 for stability. However, there is no noticeable difference from 5200 - 4000. (There are many other reports of similar issues).
nb. My machine is for digital audio / video work, hence the large RAM requirements.
But it is unlikely you will need more than 32 for MSFS tbh. I think last time I checked it used around 17GB. (with a 4090 24GB).