Seems best to do a cold boot before you load the game. Mine black screened on the very first start up but a reboot sorted it.
Pretty sure the Beta has a memory leak because if you exit out the game and then reload it stutters. A reboot sorts it completely.
How much RAM you have? I'm running 16GB and BO3 Beta stabilized to around ~5GB RAM used with peaking around 5.3GB for short periods of time. If Beta is designed to hog RAM like no ones business then you don't need memleak to run into issues in that regard.