Dk'tronics Silicon Disc

Box and Manual for the memory expansion (464 version)

A closeup of 6128 version

A 256Kb RAM expansion for the CPC. This combined with the DkTronics 256Kb memory expansion (advertised as such) would give the CPC an additional 512Kb RAM in the case of a 464/664 or an additional 448Kb RAM in the case of the 6128 - ie: in all cases a maximum of 576Kb RAM.

Silicon Disc Versions

• "dk'tronics Silicon Disc" cartridge
• "dk'tronics Silicon Disc Operation System" cartridge

The difference here is probably, that the first cartridge contains plain RAM, the second additionally a BIOS ROM with RSX commands for accessing the RAM disc.

Other Versions

Dk'tronics also made the "Dk'tronics memory expansion". Not sure if/how it differs from the "Silicon Disc". Maybe it's just renamed and contains exactly the same hardware... or maybe one of the devices is battery-backed, and the other isn't...?

An article in Amstrad Action described how a Silicon Disk can be converted into a 256K memory expansion. I think this applies to the RAM part only.