BigRamPlus
256 MB Memory Expansion for Amiga 3000(T)/4000(T)
BigRamPlus is a memory expansion with 256 MB RAM for any Amiga with Zorro-III slots, i.e. Amiga 3000, 3000T, 4000 and 4000T. BigRamPlus is only guaranteed to work with the original daughter boards of these computers, there is no warranty it will work properly with third party bus boards made by Micronik, RBM, Eagle, Elbox, etc.
Please note: AmigaOS 4.0 does not permit the use of a Z3 memory card, the computer won't even boot into the OS. AmigaOS 4.1 can use the card's memory as swap memory.
Source: http://www.vesalia.de/e_bigramplus.htm