If you were me

If you primarily use your PC for music, I wouldn't pay out that much extra just to get faster DDR5 RAM. To my knowledge, the amount of RAM is more important than the speed of it, because you mainly use it to "store" your loaded libraries so they are ready to load and play quickly - and I think the difference in speeds is basically unnoticable in this case.

Personally I would go for the extra 64GB which takes you to 128GB and then rather invest in the best possible CPU instead. I currently have a Ryzen 9 3900x and intend to upgrade to a Ryzen 9 5950x at some point.

Some things you have to keep in mind are:

a) Does the MoBo support both DDR, and how much max. I guess you know that

b) What is your existing RAM model, speed and CAS Latency. Ideal is to match exactly but unfortunately there's been known issues in terms of chip consistency. Meaning, you could buy 64 extra ram, same brand, model, specs but the chipset is from another vendor. Which it may result into incompatibility and won't post (will hang on boot up or will boot with X amount of RAM, not all.

c) Ram is Ram in terms of space, so either ddr4 or ddr5 if you have 64 ram and you get in a situation where the system tells you you are out of ram, it won't matter if it's ddr4 or 5. If your Mobo is made for Ddr4 and ddr5 it's probably more prone to work better with DDR4.

d) 64 I think it's enough, one way to see how much it holds, loading VEP Pro and instruments will tell you when you run out of ram, so if you don't have stutters, pops, lags, no more ram is needed, and still in lieu of a lean workflow, avoid having all instruments loaded uf you're not using them, and also render to audio those who are ready.

Thank you. I just did the computer purchase and purchased a cpu more powerful than another one of my other options. I don't plan to update the cpu unless I really have to.

Ok. Ty. yeah so far I have not come close to utilize the full 64. I will wait. There is a good computer store near me that will sell me some ddr4 and install it for me. Hopefully they'd have an idea of what would be compatible.

Right now everything is working perfect (knock on wood) w/ 64 so I'm gonna let it be, I guess. If I upgrade, however I'll go ddr4, based on the responses I got to this question

If you're routinely hitting 65-75% RAM usage with current projects, then definitely get an additional 64GB of DDR4. I don't think DDR5 is worth the money at this point (if you can even use it with your current system per other responses above), especially if it's for "just in case" scenarios.

If you aren't pushing your RAM capacity, it's still not a terrible idea to add the extra 64GB - it's one of the most cost-effective upgrades you can do - but there's also no urgency to it unless you see prices start jumping up.