There's an interesting point here and that is, the only reason I wanted to run windoze in the first place was because my old machine wouldn't play elder scroll online in PVP mode but the new machine runs it fine under linux which is what I prefer anyway so I might just use the other drive as a spare and/or backup drive to dump stuff. I'll probably leave it with windoze on because... why not But not actually use it 'in anger' as it were.
Just ran a speed test under linux on the two drives. This is the Crucial drive I had originally... This is the Kingspec... That might go some way to explaining why the performance in windoze isn't as good as I was expecting and why the machine seems to be faster under linux.