Video capturing at 60fps (Win+Blackmagic)

I just realized that my video card (Blackmagic intensity shuttle USB 3.0) is only capturing at 30fps instead of 60. I am on an Alienware / Nvidia 1070. I believe the problem is the OS settings: the HDMI virtual display for capturing is set at 30fps and if I try to bring it to 60 it gives me a black screen. I have been scavenging the internet for some info about this but I guess it's too specific: maybe some of you have had the same problem?