Got a CRT? Use Refreshlock!
What is monitor Refresh Rate?
Monitor refresh rate is exactly what it sounds, it refers to the rate at which your screen refreshes. So if your refresh rate is set to 60hz, your monitor is redrawing the image on your screen at 60 times per second.
But i heard refresh rates don't effect LCD's?
WRONGG! This is the biggest misconception floating around the internet today. It boggles my mind how many flame-wars are going on about this topic when it is very easy to prove. Yes a LCD screen will not suffer any flickering effects from having a low refresh rate. Instead, it will suffer through a limited frame-rate. Because of the way video cards render images to the screen, LCD's are still completely effected by refresh rates. It is extremely noticeable if you compare a CRT and LCD monitor side by side. The biggest problem with LCD's is that they will not allow you to go past 60hz or 75hz in any resolution, so at best, you will only see 75 frames per second in game. Crt's have the ability to go as high as 150hz in lower resolutions, making them better for gaming. Those of you who don't believe me can simply enable v-sync (vertical sync) in game. Once enabled, v-sync will render exactly what your monitor is capable of displaying, and depending on the make of your LCD, your frame-rate will be roughly 75, at best :(.

- Make sure you don't go exceed your monitor's maximum refresh rates. If you are using refresh-lock and are unsure what your maximum values are: refer to the picture above and check the box marked "Always use the fastest safe frequency for mode".
- Make sure to test your settings in game through conjunction with the V-sync and frame-rate commands (like fps_max), to make sure you're truly getting whatever hertz you set it to.
- If on an LCD do no exceed 75hz, check your manufacturer's manual first.