As stated above, the latest version of ezQuake enables independent physics by default.
If you want solid, utterly smooth rendering, you'd better disable it.
Whilst it works, it's generally not as smooth as a conventional vsync'ed display unless you're careful about picking the values for cl_physfps and vid_displayfrequency so physfps is a submultiple of the refresh rate, eg 120 refresh, physfps 60 or physfps 40.
But, by doing that, you're achieving rendering fluidity at the expense of gamestate updates, Unless of course, your display is capable of refreshing at 144 or 154Hz.
Setting physfps and refresh to the same value just don't give smooth rendering.
Doing it the conventional way:
"+set cl_independentphysics 0" on the command line.
choose your display resolution on the command line.
"vid_vsync 1" at the console/in your cfg file.
Set the display frequency to the nearest valid refresh rate _below_ the update rate of the server you're joining.
eg for a default qw server (72pps), set vid_displayfrequency to 70Hz
eg for a typical qw server (77pps), set vid_displayfrequency to 75Hz
If running a server locally and have a monitor which can do 100, 120, 144Hz at your preferred resolution, and you're not too bothered about the slight change in game physics at higher update rates try:
serverinfo maxfps 120
vid_displayfrequency 120
Oddly, you can set the displayfrequency to the same figure as the server update rate at higher values like 120 or 100 without getting jitter/stutter, whereas at lower values like 77 its quite noticeablely juddery and you have to drop it to the next valid value down.
Also ... ezQuake gripes
Someone please make it save/load the current config on startup/exit, eg to ezquake/config.cfg.
This doesnt preclude the cfg_save/cfg_load feature (that should always override whatever is in any config.cfg), it just means that some newbie who doesnt read documentation (like most) doesnt spend half an hour setting up controls, tinkering with visuals etc, only to find that when he quits and then restarts all his changes have been lost.
Pickup flashes now hurt rendered fps badly. If vsync is enabled and you pick something up, it loses sync. Even in a situation where if vsync were off, the rendered framerate would be many times that of the displayrefresh. Similar results on both an 800MHz PIII (GF2) and a 2.8GHz Opteron (7800GT).
First startup after clean install. Go straight to options, attempt to assign mouse buttons. They don't respond ?!
At least, not initially anyway. Start a local server or SP game, and suddenly you can assign mouse buttons ?!
Cut the sound volume/system on level changes. On recent versions of ezquake the last sound effect played immediately beforehand loops for the next couple of seconds until the level finishes loading.