User:Lemma/GPU-Performance

Primer

Several popular graphics cards out there - especiall NVIDIA ones - exhibit performance problems with KDE4. These performance hits mostly concern Plasma - the KDE4 desktop - and KWin - the KDE window-manager. Generally speaking this isn't due to KDE4 being unoptimized but a problem with the cards' graphics drivers. This page encompasses certain problems that might arise and how to get rid of them.

Symptoms

This section summarizes several symptoms you might encounter and tries to explain possible causes.

Resizing certain windows is choppy

Explanation

This might be due to your card advertising ARGB Visuals (basically translucency) without having proper support for them. Applications/windows concerned are the plasma desktop, the krunner dialog (Alt+F2), plasma's Add new widget dialog or a konsole window.

Test

If you want to make sure this issue is a problem for you, run

$ XLIB_SKIP_ARGB_VISUALS=1 konsole

on the command-line and try to resize the new konsole window (setting the environment variable XLIB_SKIP_ARGB_VISUALS turns off ARGB visuals). If it resizes without problems, then this is certainly one of the problems you're facing.

General

• You can set the BackingStore options in your xorg.conf:

Section "Device"
    ...
    Option "BackingStore" "true"
    ...
EndSection "Device"

This works for some (eg. konsole) but unfortunately not all windows.

NVIDIA

• You can set the IntialPixmapPlacement with the nvidia-settings utility:

  $ nvidia-settings -a InitialPixmapPlacement=2

  This works for some (but unfortunately not all) NVIDIA cards.