are you running the elgato software at the same time? it shouldn't be running. Anyway, I think there is a newer Elgato driver out there, along with a firmware update. I dont know if that is the issue, but its worth checking out.
uninstall the current elgato software and while its still plugged in, remove the elgato from device manager (right click, uninstall, make sure remove driver is checked) then use the driver and firmware from the elgato website (not off the CD).
I'm not sure if this is the issue, because the encoder and video frame times are horrible. what else do you have running?
Lastly, After you do the proper driver, remove and readd the elgato from OBS but make it a global source this time.