SeekingTao, 4200-128MB cards nearly all use 4.0ns Samsung/Hynix which is technicly sound up to 500mhz but many average 550mhz! The cores in all GF4TI are essentialy identical and all stock coolers are all equally good, hence 275 should be easy while 300+ is not unrealistic. So 275/500 should be very easy for you while about 300/550+ isn't out of the question, you should beat 4400 stock but you'll need a special 4200-128MB card to challenge the 4600, still there's only about 10% perf diff between 4400 and 4600 anyway! Just raise the clocks slowly and test thoroughly at each setting, anything you do get is a bonus anyway. For GF2/GF4MX the RAM clock is by far the most critical thing but GF3/GF4TI benefit very equally from both core and RAM so fin the limit of both and then back off a couple of notches in the long term.
GoodRevrnd, Rad9700 really shows up the age of the 3Dmark benchmark particularly at the standard 1024x768x32 without any AA or Ani. If you up the res to 1280x960 or 1600x1200 and enable Ani & AA you'll see a very diff picture! There is a big diff between VIA KT266 and KT266A, but this shouldn't hold you back too much and anything over 8000 marks isn't hugely noticable anyway!