Sorry to zombie this thread but a few things to followup and hopefully help others):
Nvidia Inspector destroys my particular setup. I'm not sure how others are able to use it while streaming at all, but particularly on mine it was the main source of preprocessing time and log errors.
Moving on though, even without Inspector I was unable to stream at 30FPS/3500kbps/480p and play certain games (Titanfall, Phantasy Star Online 2, Team Fortress 2, etc.) at a minimum of 60FPS/1080p, in-game frame drops (down to 40 and sometimes less) everywhere that wouldn't show up as problems in the OBS log files as well. This was rather confusing to me as I believe streaming to be a mainly CPU intensive endeavor, and the i5-4670K I had should have definitely been able to handle both streaming and playing the game. A GeForce GTX 760 should have been able to handle any GPU strain as well.
In the end, for some reason buying 8 more GB of RAM (increasing from initial 8 to 16) and a non-stock heatsink on my processor allowed me to finally stream Titanfall at 30FPS/3500kbps/480p while playing at 60FPS+.
I don't know why this is, all logic to me dictates either the processor or the GFX had to be the bottleneck in playing smoothly while streaming, but a heat sink doesn't exactly make my CPU go faster (I initially intended to overclock but I haven't gotten to it yet), and I didn't think the RAM increase would as well.
That being said, I still have the sometimes random issue where the bitrate listed in the lower right of the OBS window will jump to 10000-20000 kbps even though I have set a static CBR of 3500 at all times now, again this doesn't show up in the logs or get listed as "Frames Dropped" the frames in-stream just adjust themselves to 1 while the burst of bitrate happens.
