The fact is, 18 - 30 fps is NOT good enough, 30+ could be acceptable for some, the poster did say 30 - 45 fps, which is reasonable.
i agree with this.
if we are speaking on averages, then in no way shape or form is 24 acceptable to me.
lets take my last 3 video cards and one game (guildwars) for example.
ati x1300
evga 8800gts 320
evga gtx 280
the x1300 averaged about 20fps in guildwars
the 8800gts averaged about 50fps
the gtx 280 averages over 200fps
with the x1300, that 20fps as an average, was just tooo choppy for me. this dips from low to high in fps was just too much for me. it would dip into the single digits during heavy play and boost up to about 30fps during light play. this wasnt good enough.
with the 8800gts, boy was that a nice upgrade over the 1300.
even with the average of about 50fps, the min fps was still not enough for my tastes, diping below 20 at some points. and maxing out @ 60. but most of the time it ran over 50fps.
now i have the gtx 280, its just flawless @ over 200fps average. never dipping below 100, and sometimes reaching over 400. i know this may be big overkill, but this is how i like my games ran, flawless.
the only lag i get is from server or my connection (ping).
so by saying 24fps average is just as good as 60fps ave to the eye, is just not right, because you have to take in the min vs max into consideration.