You should only use Zorro-II ram when absolutely necessary on a 32-bit system as it slows the CPU down to a speed comparable to a 7 mhz 68000 due to the way this memory has to be accessed.
As already mentioned in this thread the Zorro-II bus can only address 8 Mb, and that includes any zorro-II graphic boards you might have installed. This means that for example if you have a Zorro-II gfx card with 4 Megs of ram you have only 4 megs left for other purposes.
Obviously any memory is better than none, but its priority should be the lowest so that it does not get used unless absolutely necessary.