I just finished building my new PC, and since it has been a while since I did this last time, I'm a bit confused about the M.2 slots and storage using them. I have a PRIME Z790-P motherboard with multiple M.2 PCIe 4.0 X4 slots available. Currently, I have a 2TB NVMe drive in the M.2_1 slot (the one for the CPU chipset, I think?). I was wondering if I could add more drives to the remaining M.2 slots. I read something about a performance hit if you do that, and the drives might end up only using x8 or even x2/x1 PCIe lanes. I also read something about it possibly making the GPU run at 8x PCIe lanes.
Again, I really don't know much about this, and I couldn't find a conclusive answer on the web. So, to sum it up, can I add additional NVMe drives (preferably 4TB ones) to the remaining slots on this motherboard without the risk of compromising performance?
Yes, you can use the other drive slots as well. Your motherboard manual might say if the GPU slot will drop to x8, but even if it does, somebody told me recently that the performance hit was very small - less than 3%. On my 690 Hero, I have all slots filled and I'm still on x16. It depends on the motherboard. So if you want the storage and the speed falls on the main GPU slot, you probably won't even notice.