Expansions bigger than 64K combine the CPC6128-style mapping with some formerly unused chips in the fourth Gate Array register:
Gate Array, Port 7Fxxh: 7-6 Must be 3 (aka Gate Array Register 3) 5-3 Bank number in 64K units (for expansions bigger than 64K) 2-0 Bank mapping in 16K fragments (as on normal CPC 6128 Gate Array)The 16K fragments are consisting of 8 banks. Banks 0-3 are the internal RAM, banks 4-7 are external RAM (taken from the currently selected 64K block).
== Capacity ==
* [[Dk'tronics memory expansion]] - 64K and 256K expansions
* [[Dobbertin Memory Expansion]]
* [[CPC4MB]] (DIY) - compatible with standard 512 Kbyte expansion (plus extra non-standard 3.5 MBbyte)
* [[RAM BOX]] 512Kb memory expansion '''(is that lowercase "b" meaning 512kbit=64Kbyte ???)'''
* The first 192K (of total 512K) in [[Aleste 520EX]] are standard compatible
== Non-Standard Expansions ==
* [[Inicron RAM-Box]] - not fully compatible with standard expansions
* [[Otten & Fecht 1 MB RAM-Disc]] - Accessed through I/O ports (RAM is not mapped to memory)
* [[Vortex Expansions RAM card]] - non-standard
== Expansions that are unknown how they work, and if they are standard or not ==
* [[RAM7 2Mb memory expansion]] - is that 2Mbit or 2Mbyte? what I/O ports would be used to access 2MByte?
* [[Inicron RAM-Box]] - not fully compatible with standard expansions
* [[Data Media SP64]] - all unknown
* [[Dk'tronics Silicon Disc]] ([[Dk'tronics]]) - all unknown
* [[Phoenix M64]] - all unknown