fps_max
fps_max is a console variable available in all 
Source games.
This is a ConVar you can enter in to limit your frames per second. It is recommended that you limit your frames to the refresh rate of your monitor, because any frame rate above that is wasted, and could cause the monitor to have screen tearing issues, causing the systems to make coil whine noises due to higher power draw. Furthermore, having more than around 1000+FPS in a Source games (or 100+ in 
GoldSrc) may cause the timing-related issues (such as the game running faster than normal) and potentially causing the game to stutter (or cause the servers to teleporting you back where you should be)[1].
Syntax: fps_max <frames per second>
Note:Default: 300 FPS, 400FPS in 
CS:GO.Example: If you wanted 85 frames per second, you would type in the console: fps_max 85
Quotation marks around strings are not always required, but should be used to ensure that special characters, such as spaces and semicolons, are not misinterpreted. For number-only strings, quotation marks should not be used.
Note:On listen servers, going above 1000 FPS may cause pseudo-speedhacks, where time seems to have sped up. It should not happen on dedicated servers.[confirm]References
- 3klikphilip -
1000 FPS in CS:GO????
