Should I choose the Ryzen 5800X3D or 5950X for a high-FPS AM4 gaming build?

The 5800X3D is the better fit for the RX 9070 XT if gaming performance is the priority. The 5950X can still deliver high frame rates, but in CPU-bound games it may leave performance on the table, particularly with medium settings and upscaling. Before buying, it’s also worth checking the cost of an AM5 bundle with a newer X3D processor, motherboard, and DDR5 memory. If that is only slightly more expensive than the 5800X3D, it could provide a better upgrade path; otherwise, the 5800X3D is the straightforward AM4 upgrade.

For your main goal, I’d choose the 5800X3D. Its large 3D V-Cache gives it a substantial advantage in many games, especially when you’re targeting very high FPS at 1440p with reduced settings. The 5950X is much stronger for heavily threaded productivity work, but it generally won’t drive a powerful gaming GPU as well in CPU-limited situations. Use the GPU’s hardware encoder for streaming, then reconsider the server CPU later instead of buying around a future use case.

The 5950X is still excellent for rendering, compiling, virtual machines, and other multicore workloads, but it is a fairly excessive choice for a typical home server. Services such as file storage, media serving, containers, and a few lightweight VMs usually don’t require sixteen cores. It can also use more power at idle and under load, so a lower-power AM4 chip may be a better server option later. The 5800X3D also tends to retain its value well, so you could sell it and change CPUs when the system is repurposed.