Slow GUI issues with ardour.org binaries: resolved
Several people have reported "slow GUI" issues with prebuilt versions of Ardour from ardour.org when used on Linux systems with Nvidia video interfaces.
This problem is caused by a bug in the Nvidia driver. It has been fixed in later versions of the Nvidia driver. There is a workaround for this that will fix the problem for Ardour itself: set the environment variable FORCE_BUGGY_GRADIENTS (to any value) in the context where Ardour will run (precisely how to do this is slightly distribution dependent, so details for those who don't know how to do this are left for distribution support channels). This environment variable tells Cairo, the drawing library that Ardour uses, not to rely on the video driver's gradient drawing capabilities (which in the case of these older Nvidia drivers is broken).