Red Hat Bugzilla – Bug 539525
Terrible performance with KMS
Last modified: 2009-11-20 12:52:00 EST
Description of problem:
While using KMS, the rendering speed of xorg-x11-drv-ati driver is terrible. Glxgears shows only 700 FPS, and OpenOffice Impress animations are very slow or even freeze the system.
On the other hand, if booting with the nomodeset option, rendering speed increases a lot: glxgears shows 1700 FPS, and OpenOffice Impress works normally.
The graphics card is ATi Mobility Radeon X1600.
Version-Release number of selected component (if applicable): xorg-x11-drv-ati-6.13.0-0.10.20091006git457646d73.fc12.i686
Acquire ATi Radeon X1xxx card, boot with KMS enabled and measure rendering speed. Then boot with KMS disabled and remeasure rendering speed.
Steps to Reproduce:
see How reproducible.
Rendering speed is slow.
Rendering speed should be at least as fast as without using KMS.
I supposed that KMS is designed to increase the graphics performance, not to decrease it. Am I wrong?
*** This bug has been marked as a duplicate of bug 526967 ***