1764 Ram Expansion Unit (REU) 256kb

When the Commodore 128 came out it was clear that this series of computers was also intended for business use. And for many even 128 kb wasnt enough. Commodore released some memory expansion modules, the 1700 (128kb), 1750 (512kb) and then the 1764. The two first ones was only supported by the 128 and the 1764 was the one that was released for the C64. Soon after its release a lot of computers were coming in for repairs because the PSU wasnt powerful enough when the REU was plugged in. So Commodore released this bundle with the REU and a powerful 2.5 amp PSU. The 6502 cannot address more than 64kb of memory so a special paging mode would have to be used in order to copy memory to and from the REU. Applications like GEOS benefitted greatly from the REU and enabled the use of a very nice ram drive to speed things up considerably.

Collection

As usual I found this on ebay UK and was quite lucky to find it complete with box manuals and all. Its quite heavy due to the powerful PSU. And the unit sticks out quite a bit in the back of a C64.