What kind of computation do you perform?
Is more cpu or gpu oriented?
Also be sure to choose the right motherboard, that can support easily 4*16Gb of ram.
Not sure all motherboard are to the same when you need such amount of ram, clocked at least a 2933Mhz.
The computations are CPU oriented. I am thinking about the X470 AORUS ULTRA GAMING (rev. 1.0) | Motherboard - GIGABYTE Global
But, who else has a stable Ryzen 5 Raven Ridge configuration with 4 DIMMs at 2933MHz? Thank you for your comment, benman2785. However, I'd like to hear from someone else that the mentioned configuration is stable with a Ryzen 5 at 2933MHz.
To be honest if you are mainly focused on cpu workloads, i would advice you to think about switching the 2400G with a R5 1600/2600.
You could buy a cheap second hand pci-e gpu, just to handle basic desktop loads, then maybe get a decent gpu later on if you need.
Doing that you would get 2 more cores and 4 mores threads, if your compute workloads are heavily multithreaded using many thread/cores as possible, you will noticeably reduce your compute time or increase your compute power.
About the ram, unfortunately with the current prices, it will not be easy to fin a cheap good 64Gb kit at 2933MHz, where i live, it would cost far more than the cpu/mb combo, more than 500euro. Also as we noted before, you need to check if the motherboard can handle that amount at that speed, not sure cheap board would handle that correctly.
To sum up, think about which cpu would really be the best for you, an APU quad core and bare six cores. Knowing you could also upgrade later on to a R7 1700/2700.
Check carefully the ram amount and prices.
buy the ryzen
dont use XMP - make all settings by hand: you will run your ram at 2933
MAYBE you need to oc ram and lower-multi
ps on AM3+ i run 4x4G 1866er as 234MHz x8 = 1872MHz in CL9 - instead of 200MHz x 9,33 // and i could even go higher // XMP fails to load at 1866er CL9 // so you see - if you do it with your own hands you have benefits // actually you benefit even more on RyZen with that - your InfinityFabric gets faster that way