SSD with 80 MB/sec sustained write speed - is this good enough for a boot drive for non-demanding user?

I have access to some old used QLC 1TB SSD drives for cheap. They initially looked great with 350 MB/sec write speed but after less than a minute it slowed down to 80 MB/sec where it stayed there for 10 minutes or so until I got bored of watching it. The sustained writing was done by a Windows "full" format and observed via Task Manager. Not sure if this was a good test but it was all had. Is this fast enough for a moderate user (not power user) as a Windows boot drive? The small files they use would be less than 5 MB so it should be a split second to save those files.