Asuming your CPU is 266 FSb then SW2(off,off,off,off,on) jclk 2-3 selected, this is at end of AGP card there is a jumper with 3 pegs the little plastic tab needs moved to short 2@3, on my board it shipped with 1 and 2 shorted for a 200mhx bus speed. This is really a good time to read and use your manual! look on page 3-5 for multiplier, and 3-6 for the jclk. This is assuming our manuals match so you may need to search. I hope this helps.
edit my board is rev 1.0 if your is defierent this may all be wrong