Stuttering happens when there is insufficient RAM and your system "dips" into your HDD for additional data. The game then temporarily suffers in framerates (even though your pc can put out more than decent frames)
I know RAM is not the case here but it looks like it stutters. The other exes? So I'll click on the "nexuiz-sdl.exe" instead of "nezuiz.exe"? Okay I will try that.
No (if am the one you asked) I did not overwrite my previous version, I took it out, cleaned my registry and then put Nexuiz 2.3 in C:/program files/nexuiz.
Also, it's not the input as when I just run and don't fire any weapons, the stuttering is there always. Slight, but noticeable.