Why is qt or gtk faster on some people's system?

[Infohawk]

I've used qt and gtk my system now (Debian unstable) and have both kde and gnome desktops installed. KDE and qt apps are faster for me. Even when I'm in gnome, qt apps are snappier for me. Sure, loading the first qt app in gnome takes longer, but it's still snappier. And in KDE, qt apps start quicker than gtk apps start in gnome. So for me, qt is quicker.

But then I read in places that it says gtk is quicker for people. I genuinely believe them. I don't think this is just about the fanbois saying one is faster. I prefer gnome and use it day-to-day but for me qt is faster and for other people it seems the opposite.

Is someone wrong or is there a possible objective explanation for this? Is qt faster on some systems and gtk faster on others?

Also, is gtk fast for anyone? I have a 1ghz duron only, but I've heard even on new systems gtk still can seem slow, is this true?

 

[Nothinman]

I've never noticed any slowdown with GTK and I can't speak for QT because I never install it.

 

[Barnaby W. Füi]

Since GTK2, QT has always felt faster for me.

But speed isn't necessarily what you think it is. Tearing and artifacts can make things feel slow when they're really not. OSX might feel faster when resizing a window, just because it does it fluidly, without any tearing or artifacts, while in current X11 (without new compositing extensions), you'll usually see some ugly junk when resizing, which makes it feel slower (like it can't keep up), even though it's measurably faster than its OSX counterpart.