Hi, I searched a lot! I mean I read every single post about Gnome-shell slowness in the world wide web!!! but I couldn't find my answer.
I have this problem too. Gnome-shell responses very slowly to switch between different applications. now, I have 5 windows open: totem, firefox, terminal, and two nautilus. I'm typing here, in firefox. when I hit the super key, and then I choose firefox, there is no lag. but if I choose another window, there will be a lag. an annoiyng lag! and then if I hit the win key again, and choose the same window, there is no lag, but choosing another window produces a lag. even with only two windows open, (not even five).
I didn't have graphic problems in gnome 2 with compiz enabled.
1215n Asus eeepc laptop
cpu: atom 1.8 Ghz
VGA: intel N10 family + nvidia ION. I have disabled nvidia with dkms-acpi_call. It was also disabled in compiz...
Mesa drivers: 8.0.3 (latest)
Fedora: 17, updated today.
I had this problem in ubuntu 12.04. so it might not a fedora issue, and as I didn't have graphic problems in compiz and 3D effects, it could be a gnome issue. but if this is gnome, why there is people enjoing their gnome shell without such problems?!