Hello ,
i use phoenix 2 x SD/HD SDI capture card with catalyst V4.4 M466 on MACPRO 5,1 - Mac OS Mavericks 10.9.2 - 2 x xeon 2,4Ghz , 6Go RAM DDR3 - SSD120Go -- Nvidia GTX280

then after test with a broadcast video setting

CAM 1080i--> HDSDI --> switch PANASONIC HDSDI --> BMD Hyperdeck2 recorder 1080i --> loop out --> phoenix card in catalyst --> capture in 1920x1080 HDSDI in catalyst

then we have between 4 to 6 frame max to late ...

it's a vey good card .. just install the last driver on your Mac and it's OK

best regard

Yves