Did you try the Oculus S yet?
If not I'd get it up and running, from there try some demos and see how it performs. While your doing this run HWmonitor in the background to check usage but honestly your probably going to need to upgrade the CPU & GPU or severely lower the graphics to make sure it's smooth and you don't experience motion sickness. If it runs poorly even on lower settings then return the Oculus and use that $400+ to upgrade your current system.
VR does run smooth with these specs (or an RX 580). *By smooth I mean just gaming normally, trying to game on Bigscreen or a similar program is difficult to run and requires a significantly more powerful GPU to do (Division w/1080ti required me to lower the settings from Ultra to Low to maintain 60 FPS), even trying to stream VR can be quite taxing on systems.
PCPartPicker Part List
CPU: AMD Ryzen 5 2600 3.4 GHz 6-Core Processor ($119.99 @ B&H)
Motherboard: ASRock B450M/AC Micro ATX AM4 Motherboard ($74.99 @ Newegg)
Memory: Team T-FORCE VULCAN Z 16 GB (2 x 8 GB) DDR4-3200 Memory ($54.99 @ Newegg)
Video Card: Zotac GeForce GTX 1650 SUPER 4 GB Twin Fan Video Card ($159.99 @ B&H)
Total: $409.96
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2019-12-16 16:37 EST-0500