I just switched to Mavericks (10.9.4) from the latest Mountain Lion and noticed that my screen, especially noticeable with Mission Control, lags a bit when using the discrete GPU.
I switch to the dedicated card using an utility called gfxCardStatus, but using the "official" method through
System Preferences -> Energy Saver -> High performance yields the same result.
Additionally my mouse speed seems to be bit lower when using the dedicated GPU. This is not visible in the video.
I'm on a 15 inch Mid 2009 MacBook Pro 5,3 with an integrated
GeForce 9400M card and a dedicated
GeForce 9600M GT. All worked fine before on Mountain Lion. The Mavericks system requirements state that my laptop is supported.
I've tinkered around and found that the GPU that is working on startup functions correctly. So if I restart while the discrete GPU is used all works fine and switching to the integrated GPU now yields in the screen lagging as shown in the video above. Switching the GPU back to the one that was in use during startup gives smooth graphics.
How can I find the origin of this problem? How can I solve it?