I have a Mid 2007 iMac 24″ with OS X v.10.11.6 with ATI Radeon HD 2600 Pro 256 MB. It runs Kodi 16.1 fine and Mythtv Frontend fine.
However, on Kodi 17 I have choppy video and no lip sync. If I turn off VTB acceleration it works normally as it did back on Kodi 16.1
The version of Kodi 17 is Git:20170201-a10c504, the one linked to on the Download page.