There was also a theory that it was caused by certain graphic drivers.Sure, nobody can do that. The original suspicion however was that it was the older systems who caused the lag, and we added anecdotes where it didn't.
So rather than complain like dozens of people have done in this thread, it might also be useful to post all that data to Andrealphus, both for people who experience lag, and those who don't (not just OS, but also drivers that could impact - graphic one being a decent shout - HDD / SSD could also be an issue - I don't know). Even better, post the same data again when a change occurs between experiencing lag and not experiencing lag, so that the issue can be more easily be pinned down. If it is supposedly caused by graphics drivers, but no drivers were updated, at least that can be ruled out.
Very hard to figure out what the issue is, when you don't experience it - so would need a bit of a community effort to narrow it down sufficiently so that the dev can actually start solving it.