Thanks, it's a 2011 MBP with upgrade to 8GB RAM from 4GB, and an Samsung 860 SSD.
Only had the problems with Sierra. So thinking that maybe 8 isn't enough. I did have lightning speed with that and new SSD on Snow Leopard. And stupidly expected the same kind of reaction with Sierra.
Thanks Viking, yeh I saw that, It's amazing nobody has given a yes or no, that's why I asked the question on here actually. Surprised it didn't mention it, because it does show it works on Sierra. But nobody has passed comment on that at all. If High Sierra is a big improvement, then I'd probably invest in the 2018 version