VSync is fine for most games but not for Call of Duty. You will need that steady 125/250 FPS otherwise you will get raped. For example - a guy with 60FPS going against a guy with 125FPS (they both use the same gun and have same level in skill). Its obvious the guy with 125FPS will win because his gun will shoot faster and has less recoil.
In cod4, higher frame rate even made you jump higher.
In cod4, higher frame rate even made you jump higher.