I can report that qBittorrent v3.0.11 is working fine with Windows 8 Pro x64! Sadly, it required a complete clean install to find that out I love this little torrent client and it's allowed on all/most private trackers as well. Or rather, it's not forbidden like tixati, which I like too.
Can you help me with configuring qBittorrent with my VPN? I've not looked into the advanced options too much, but does it have something to do with the "network interface"?
Ok, after a few weeks of testing, I have to retract my previous statement. Small freezing still occured randomly and yesterday it kept freezing so much, before and after the update, that it was unusable. It almost seems that adding more torrents makes it worse, well, I'm almost certain this is the case.
Therefore I switched back to utorrent 2.2.1, probably the best client now that QBittorrent is not working for me.
Another possibility for the sudden massive increase in freezing/crashing could be some recent windows updates I think, but I that's only a hunch. Something is seriously messed up with either Qbittorrent or Windows 8, which prevents a perfectly smooth user experience.
Well, since it is a free program, I can't really complain of course. And I don't really understand why I switched to nasty windows 8 in the first place.
How many torrents do you use? Does the freeze happen even with only one torrent in the transfer list?
Note: I mean total number of torrents. paused+downloading+uploading+queued+checking
There were about 30 torrents or so, all supposed to be seeding. When I first started using qbittorrent on my freshly installed windows 8, it seemed to run fine with only a few torrents in the list.
I still have a windows 7 x64 Ultimate laptop with qbittorrent installed, but there have never been any issues. Perfectly stable. It HAS to be some interaction with windows 8 causing this. really gonna miss this client.
Alright, I'M DONE with this windows 8 bullshit system! If I can't get my favorite client to work on it, then I'm done with this system. It offers no real benefits for me and is just freaking me out. This tiles shit is completely useless and annoying. I feel like windows 8 tries to transform my high-end gaming pc into one of those nasty smartphones, which everybody runs around those days. All the additional "features" of Windows 8 are ridiculous and meaningless, what a waste of 100€
I'm really sorry for your problems, Pyro, but I feel too that 7 Ultimate is the way to go (I tested Win 8 only on friends/relatives computers and never got any appeal to try it...). I don't want to bash Win 8 here though, this is just a personal opinion.
Did you tried the solutions in my post above? If so, what happened?
I don't really understand your solution and your problem :/ But I never had any memory/cache problems and Qbittorrent WAS running fine with windows 8 at first, though never perfectly stable. I will downgrade either way now, for some other reasons too.
I love this little torrent client and it's allowed on all/most private trackers as well. Or rather, it's not forbidden like tixati, which I like too. 
really gonna miss this client.