What's your issue with the video exactly? Smoothness? General quality?
Your game appears to be running at 640x480 so that's not helping quality. I was running GLQuake at 640x480 in 1997 when the resolution was actually impressive for games. :P That said I understand CS:GO players have all sorts of idiosyncrasies about their game configuration, and your system isn't the best for recording high definition videos anyway.
Your YouTube video doesn't correspond to the log you posted, the video appears to be running at 16:9/720p yet you recorded at 800x600 in the log. Wrong log? Wrong video?
Scene buffering time should be set to 700 under Settings > Advanced to make sure audio stays in sync.
Preset should be changed to ultrafast under Settings > Advanced to reduce your CPU load. With your current recording settings quality shouldn't be noticeably impacted.
CS:GO's frame rate should be limited to something near your monitor's refresh rate to reduce CPU and GPU load. You can use vsync, the fps_max cvar, etc.
