It works fine now. I had "Always Sync to Vblank" selected in DriConf, and that apparently didn't get along with the "Sync To Vblank" in Compiz. Once I changed the settings in DriConf and restarted, sync to vblank in compiz worked perfectly. As to why I didn't have this problem with my external monitor, but I did with the built-in LCD, I'm not sure.
It works fine now. I had "Always Sync to Vblank" selected in DriConf, and that apparently didn't get along with the "Sync To Vblank" in Compiz. Once I changed the settings in DriConf and restarted, sync to vblank in compiz worked perfectly. As to why I didn't have this problem with my external monitor, but I did with the built-in LCD, I'm not sure.