kdesktop/lock/lockprocess.cc

diff --git a/kdesktop/lock/lockprocess.cc b/kdesktop/lock/lockprocess.cc

index 5dbc4d1..7d853b0 100644

--- a/kdesktop/lock/lockprocess.cc

+++ b/kdesktop/lock/lockprocess.cc

@@ -872,7 +872,11 @@

 				info = glXGetVisualFromFBConfig(x11Display(), fbc[j]);

 				if( info ) {

 					if (argb_visual) {

-						if (info->depth < 32) {

+						// Xorg can only use GPU compositing for ARGB32 8:8:8:8 visuals

+						// Ensure the selected visual is 8 bits per RGB

+						// Selecting a non-8-bit visual will result in stuttering and high

+						// CPU load, while Xorg tries to composite each frame on the CPU!

+						if ((info->depth < 32) || (info->bits_per_rgb != 8)) {

 							XFree( info );

 							info = NULL;

 							continue;