my fps changed from 60 to 235
i got pc lag all the time (changing max_fps from 90 to 240 seems to lower the lag but not remove it)
and when i look at a texture (anything, a wall or something) and move the mouse around (f.ex a circular movement) the texture seems to like 'hack' or something, it uhm moves, or not moves, it just swap places (just about 10 pixels or less), but it's reaaaallly annoying
a friend of mine had the same problem and he tried different things to sort it out but without luck, it works for him in aprq2 v1.17
and everything works fine for me in aprq2 v1.18

pc info
Intel Celeron CPU
1100 MHz
448 MB RAM
gfx
Tornado Geforce mx 4000