Your logfile doesn't show much at all from what I can see (Dropping 1 frame out of 12,000+ is less than what recording on my r9 290x does sometimes with BF4 on large maps)
Can you cap your fps to 60 in-game and attempt another stream please, then upload a logfile if it doesn't resolve the drop in fps issue.
Your logfile does not show your CPU to be having any issues either, which is a great sign, the same for your internet connection.