Tactical Ops Multiplayer Servers require that you have the a "validated'' OpenGL Renderer and that you have the correct version installed. Multiplayer servers check if you have the proper version and if not they will kick you out of the game send you back to the main menu.
For Tactical Ops: AoT v3.4 the best version is OpenGL Renderer v3.5, it is the newest version that allows to play on "old" servers and servers running latest ACE. This updated OpenGL renderer is made by Chris Donal (http://www.cwdohnal.com/utglr/)
For Tactical Ops:AoT v3.5 Non-ESE Servers its best to use the default OpenGL Renderer that comes in the v3.5 Community Patch. You can use OpenGL Renderer v3.5 but you can get kicked by some servers that run old outdated TOST versions. (Example v18.104.22.168)
When Playing on Tactical Ops:AoT v3.5 ESE Servers its expected that you use the ESE OpenGL Renderer.
Place the files into the /System/ folder of your TO installation.
When overwriting the default one you will get a notification to overwrite the older one.
On default settings allot of Tactical Ops (-Renderers) runs way too fast on modern systems. The game runs on the UT99 Engine and back then they didnt expect the game to run anywhere from 500 to 3000 frames per second. The engine isnt designed to handle it and starts to fast forward the ingame time and speed, based on the number of fps that are rendered.
This speeding up and slowing down effect is only there when playing a Practice Session with Bots. When you play Online Multiplayer without FPS limit the player movement feels awkward, trying to accelerate but being hold back by the server basicly forcing him to move at regular speed. Also the weapons still shoot the same fire rate, but the big downside is that you generate extra footstep sounds that only you yourself can hear.
This is a big disadvantage because you know have more sound to filter out hearing other people footsteps. So its highly recommended to limit the fps / frame limit to stop the game from accelerating. The inconsistent FPS also has negative influence on the game mouse tracking.
Another side effect is that above a certain fps between 150 and 160 some small texture bugs might happen, this first starts with things like the UT99 style dynamicly updated scoreboards you see in maps. On very high fps value's (for UT/TO) like 300+ other animated textures might behave strange, stop moving, or stop being animated etc.
Some recommended FrameRateLimit values are 120, 144, 180 up to the outer maximum of 200.
Servers with ACE will also limit the FrameRateLimit to 200.
Below are instructions on how to change the FrameRateLimit from the ingame Preferences Menu.