If the OpenAL's HRTF has been set up, it's possible to enable it in the game by using dsp_slow_cpu 1 command. For the best effect you may also use these commands afterwards:
Verify Integrity of Game Cache...
More than likely, you are having DirectX issues. Try the following:
Set Launch Options...
Some servers use Pinion advertisement, a buggy plugin that sometimes crashes TF2.
Note that some servers require you to watch the MotD for a minimum amount of time (e.g. 30 seconds)
C:\Program Files (x86)\Steam\
Once the game has loaded and the FPS have dropped below playable:
From here on, the game should increase dramatically in performance.
To increase performance:
Cinnamon, by default, skips the compositing rendering manager if an application runs fullscreen, which in turn, disables Vsync. Enabling the compositing manager turns ON Vsync and (depending on the system) slows the game down.
Anti-virus software can interfere with a file in TF2's folder, which gets updated constantly during gameplay.
C:\Program Files (x86)\Steam\appcache\stats\
C:\Program Files (x86)\Steam\SteamApps\common\
Set mat_picmip 2 to mat_picmip -1 in the configuration file.
Ensure that the lib32-libpng12 has been installed.
Enable developer console (~)