May I suggest...

max out your RAM.

Lots of CPU cores. IMHO, a few more cores are much better than a slightly faster clock-speed. (Do the math !!)

DO NOT keep everything on your C: Drive. Poser thrives on 'external libraries', which limit clutter in your core run-time. So, F:, G:, H: etc. Preferably one removable / slide.

IMHO, does not really matter how fast eg Poser loads from C: as PC will spend much more time wrangling the scene. For other apps, that load & unload modules, YMMV...

You can spend an absolute fortune on high-spec GPU cards. One things is certain, your projects & scenes will out-grow them. Unless GPU & CPU rendering can be combined, you're back to 'CPU-Only', and be very glad of those extra CPU cores...

In fact, IMHO, if you are planning to do 'many' renders', you may do better going for a comparatively modest GPU card for main PC, and spending the savings on a network-render 'Box' . If Poser's 'render queue', it uses CPU-only, so lotsa RAM and Cores, with only a basic 'office' GPU and a small, pre-loved display...