Purchased the Samsung 9100 Pro 1TB SSD during Prime Days because it was a great price. Didn’t realize his motherboard is 4th generation.
Should I return and get a 4th generation SSD or keep it and run to what the max speed will be? Will this cause any issues to the PC? The 4th generation version is slightly more expensive than the 5th generation because of the deal I got.
The disk you have is backwards compatible with PCI.e 4.0, so there's no issue using it. But it will not run as fast as it could.
ComputerBase has benchmarked the disk on PCI.e 5.0 vs. 4.0, and you lose up to 50% of the possible speed of the SSD.
That said, if you don't have any economic incentive, just keep the disk and use it. It might even outlast the PC it is currently used in.
For a gaming PC, you will hardly ever notice the difference to PCI.e 5.0 on the SSD, as disk I/O will not be your bottleneck.