Accelarators that stop at 8 MB put it's RAM into the ZII autoconfig adressspace. This adresspace is simply 8 MB in size.
Accelerators that can handle more then 8 MB use an own memmorycontroller that adresses RAM in the 32bit adressspace outside of the autoconfig adresspace. Some controllers can hanlde 32 MB max. some 128 MB and some 256 MB.
