Still, your gtkperf results are awful:
Code:
GtkPerf 0.40 - Starting testing: Sat Mar 26 17:07:57 2011
GtkEntry - time: 0.01
GtkComboBox - time: 0.40
GtkComboBoxEntry - time: 0.29
GtkSpinButton - time: 0.15
GtkProgressBar - time: 0.14
GtkToggleButton - time: 0.13
GtkCheckButton - time: 0.06
GtkRadioButton - time: 0.08
GtkTextView - Add text - time: 0.12
GtkTextView - Scroll - time: 0.07
GtkDrawingArea - Lines - time: 0.42
GtkDrawingArea - Circles - time: 0.42
GtkDrawingArea - Text - time: 0.29
GtkDrawingArea - Pixbufs - time: 0.07
---
Total time: 2.66
That's for almost
four years old 8800GT (I'm running Fedora 14 i686, NVIDIA 270.30 drivers).
It seems like you are using a composite manager or your Gnome theme is very badly optimized.