Thanks guys I'll be fine, I have two open M2 slots, which aren't shared with SATA. The 1TB (yes I pulled the trigger on that WD Black) will make a huge difference, and I can get a second one later once Gen4 prices come down.
I just keep a lot of games installed for years that I never play but want to keep around
just in case
Just a reminder/tip if people are looking at NVMe drives: Be sure to compare 4K IOPS performance, not MB/s sequential speeds. This will give you actual real world performance of loading games, applications, etc, rather than "best case scenario" of just copying large files around (unless that's what you plan on doing with it, of course)