From article <C68uBG.K2w@world.std.com>, by cfw@world.std.com (Christopher F Wroten):
Good question.
Answer: The EISA bus does move 32 bits rather than ISA's 8/(16?)
        But it still moves it at about the speed as the ISA bus.
        I think that's either 8 or 10 mhz.
        The local bus designs also move 32 bits like the EISA, but
        they move the data at the cpu speed, up to 40 mhz.
        So, on a 33mhz cpu, the local bus is moving 32bit data at
        33 mhz, and the EISA is moving 32bit data at 8 or 10 mhz.
        So the local bus should be 3 to 4 times faster than EISA on
        a 33 mhz cpu.  EISA should be about two (maybe 3) times as
        fast as ISA.

That's a very good question.  The EISA bus does have more advantages
over the ISA bus than just it's width.  For example: more/better 
interrupts and bus mastering.  But these other factors do not impact
 a video card very much.  They have more impact on file servers with 
multiple hard drives, full-throttle network cards, cd-roms, etc.