[NAME] Your question is not a dumb question. There is only a single M.2 slot for either Optane memory or an M.2 SSD. That slot is PCIe 3.0 x2 which is about 2GB/s. The other M.2 slot is for WiFi and Bluetooth combo card. I would drop the Optane, but if you decide to do that be sure you disable Optance caching of your hard drive before you remove it. M.2 SSD and Optane are mutually exclusive because of the single slot. 
Forgive me as I imagine this has been asked but I could not find the specific answer. I have a 4-year old XPS 8920 (7th generation i7) that continues to perform like a champ (used mainly for productivity and graphics/video work -- not gaming). I feel like it has lots of life left in it, but it does boot slowly these days. With solid state memory so cheap now, I'm thinking of giving it a boost by moving Windows to an SSD. This PC is already running Intel Optane drive acceleration on a 16GB M.2 drive.  If I buy a bigger M.2 drive and move Windows there, do I just drop Optane? Are they mutually exclusive? Can I run both on one drive?  (Thanks for entertaining what feels like a dumb question. I'm not terribly technical, but I did just figure out how to clone a drive and move Windows on a different PC, so I'm feeling emboldened)
XPS 8920, M.2 options, Optane and Windows/SSD mutually exclusive?