Hi Dane,
The e to e path is working so you’re seeing output but it sounds like a bandwidth issue with the data going from the Intensity Pro card to disk, hence the flicker.
As a test, you can try capturing SD video and see if the problem goes away. That will be a very clear indication that it is a bandwidth issue, possibly something to do with your PCIe slot configuration.
What model is your motherboard? Do you have any other PCIe cards installed other than your graphics card?
regards
Kristian Lam
Blackmagic Design