Ik zag bij AGN 3D deze info over een fix voor hakkende TNT framerates in Q3Test:
A few people have been complaining to me about stuttering and sluggishness in Quake3. We found out what's going on. In short, in the 188 release we changed the renderer string so that it could display TNT or TNT2, and show when SSE (Pentium3) or 3DNOW!optimizations. Q3Test looks at that string and pattern matches it to see if you were on a TNT-class board. It turns out that because we changed the format of that string, Quake3 was incorrectly setting one of its game variables, and so performance was slower than it should be. To fix the problem, you can bring up the Q3 console, and type r_picmip 1. That should force things back to the way they are supposed to be, and hopefully relieve some of the sluggishness y'all were seeing.