To render, it is more important that you have a GPU compatible with the Mercury Playback Engine acceleration, either with CUDA, OpenCL or Metal in the exclusive case of Mac, because rendering is a very complex process that does not require so much disk speed but rather GPU + CPU power. The SSD is efficient to read files faster, start the operating system in less time, open applications, etc. Or maybe if you use it as Media Cache Files to accelerate the previous ones.
The GPU is actually used mostly on the effects on the list of GPU Accelerated Effects :
List of GPU accelerated effects: https://helpx.adobe.com/premiere-pro/using/effects.html
Outside of those, which are mainly things like Lumetri, Warp, and some others ... many sequences don't involve the GPU hardly at all. https://forums.adobe.com/people/Bill%20Gehrke Bill Gehrke has needed to explain that I don't know how many times on the Hardware forum and here. His PPBM8 site, and the test of that name, is a very good way to figure out where your rig is doing good, and where it's got issues. With a real-life export out of PrPro while logging apps monitor every subsystem of your computer. Comparing the data there is the one way to find out exactly how your rig stacks up against many, many other computers in each area ... and pointing out where a hardware change is worth doing.
Follow this route of the image inside Premiere Pro...
and if you do not have active the window to select another type of acceleration Mercury Playback Engine that is not only Software Only, definitely your card does not serve for acceleration.
If your card is used for acceleration then you will have the options OpenCL and also Metal, select one of them and that's it.