You know, I had this exact conundrum a while back when I was trying to pick between a slower PCI-graphics card and a Radeon 9200 for a system with a slot 1-motherboard.
It's important to note that some slot 1-boards with VIA chipsets do actually support higher front-side-bus speeds with the proper AGP clock. Overclocking the AGP-port with 133 MHz FSB only occurs with the popular Intel i440BX-boards.
Secondly (and more importantly), even when I had to reduce my CPU from 1000 MHz to 750 MHz to accommodate the Radeon, it was still so much faster that it more than made up for the loss in CPU speed for 3D-games. A Radeon 9800 is so much faster than the MX440 that the two wouldn't even show up on the same chart! Depending on what games you want to play, the trade-off for going down to a 100 MHz FSB may certainly be worth it to get the Radeon 9800... and yes - it will even trounce the mighty GeForce 4 Ti 4200/4400/4600/4800. Of course if you can nab a 700-800 MHz Pentium III with a 100 MHz FSB to go with that card, you'll be merry like an elf left alone with Mrs. Santa. 😉