I have the Ryzen 7 5800X3D. And it's my favorite CPU, ever. Great for gaming.
Note, the max. operating temp is 90C. That said, idle temps should be around 45C, and depending on what you're running the temp will reach approximately 70C to 80C. This is normal, and again, depending on what you're running.
The key feature of the CPU is the 3D memory, specifically, it featured 96 MB of Level 3 cache, practically eliminating any latency.
Check it out: "AMD 3D V-Cache Technology"
About RAM, simply put, the more the better. Combined with the CPU 3D V-cache, having higher speeds RAM will improve the overall performance of your gaming rig. But keep in mind that the RAM's frequency may need to be set through your motherboard's BIOS. In general, the frequency of your memory kit is set to lower speeds (i.e. less than 3000 cycles). The same goes for your display's refresh rate, unless you manually set it to what your display can handle, it's normally set to 60Hz.
I hope you find this information helpful!
Sam
Your biggest fan!
CPU: AMD Ryzen 7 5800X3D GPU: AMD Radeon RX 6800XT