Your log looks fine, OBS is running great.
You do know when you ask your computer to do additional tasks at the same time as each other, they might run slower? Video encoding is very CPU intensive so it should be no surprise that games have less performance when encoding is happening.
Since OBS is running great, you might try lowering its priority one notch. That may redistribute some CPU from OBS to CS:GO. Keep an eye on the log files when you do this, if you see duplicated frames go over 1%, you probably made things noticeably worse for your video stream/recording with the change you made.
There's another way to do this, which only I and maybe one other person seem to like, and others will jump in and tell you not to do it. But I'm going to tell you anyways, because I'm a nice guy / evil person making things worse (depending on who you ask):
Set a custom x264 command "threads=x" where x is an integer close to but no greater than 12. The lower number you use, the fewer threads OBS (x264) is allowed to open, leaving more CPU for anything else running in Windows. I find a value of 9 or 10 works best. So if you take my advice, you put "threads=10" in the custom x264 command box. And see if that helps.
Why does this work? Because your CPU is hyperthreaded and x264 calculates how many threads to open based on logical cores, not physical cores. It opens 1.5 threads per logical core. Your CPU has 4 cores, 8 logical cores with hyperthreading. 8 x 1.5 = 12. So x264 by default uses 12 threads on a quad core CPU. That's just too many. If you had an actual 8 core CPU, it would probably be fine, but you don't. My testing has shown the best results when limiting x264 to 9 or 10 cores on my hyperthreaded quad core CPU (an i7 2600k).
Why do people not like this? Because some people abuse the ability to set custom x264 commands and make their encodes a lot worse. They also believe that setting the priority is a "better" solution to the problem, but I disagree.
