Freya is kind of sluggish on my Mac mini late 2009: core 2 duo, 8 GB of ram, SSD disk & gforce 9400. I am experiencing a ~1 sec delay to focus windows and when I click on apps buttons. Also the wing panel is slow as well.
My guess that it is something with Gala, because I don't have this issues with Xubuntu 14.04 (same base as Freya).
Any ideas ? Should I wait for the new hardware enablement stack ? When it will came out ?