Hey, thanks for getting replying. Yeah all of the drivers are up to date, the majority from Acer support.
I've narrowed down the problem a little further - and my HDD is split into two paritions - C & D as it was set up in factory.
I've come to realise that the issues occur more prominently when you are transferring files to the D drive. When you are transfering to the C drive things are much more responsive, although not perfect I'd say.
I tried formating the D drive recently thinking it might need it especially after reformatting Windows and that the content on it was registered to the previous 'user' (i changed the computer name / user name).
No joy though, still the same problems...