So most NVMes are downgradeable, and you only get the top speed of your default PCIe hardware, but are there any trending rules with cost vs performances? For example, are most buyers of PCIe 3.0 boards getting PCIe 4.0 NVMes for future swap out?
The speed difference between 3 & 4 is only really noticeable on benchmarks so if you thinking of getting one now, you don't lost a lot getting pcie3. Might be cheaper too.
https://www.pcworld.com/article/794578/should-you-buy-a-pcie-gen-3-or-gen-4-ssd.html
I am not sure of trends, I have a pcie4 mb with a pcie3 drive, so if anything I went backwards.
If your motherboard supports PCIE 3.0 only, then 970 PRO is better than 980 PRO (miles better).There’s a sale at my local PC shop for a 1TB 980 Pro at the same price as the 1TB 970 Pro. Which one should I get?
Can't really generalize like that, it's just case to case for type of usage and certainly type oh NVME drive. There are some with and some with RAM cache where speed is same but ones without cache perform poorly as OS/boot drives. (True for all disk drives)So most NVMes are downgradeable, and you only get the top speed of your default PCIe hardware, but are there any trending rules with cost vs performances? For example, are most buyers of PCIe3.0 boards getting PCIe 4.0 NVMes for future swap out?