US Mac specialist Trans International is enabling iBook owners to pass the 640MB RAM barrier.

The company has announced availability of a 1GB DDR (Double Data Rate) memory upgrade module for the Apple G4 iBook.

Because the iBook has only one available memory expansion slot and 128MB of RAM, the system memory capacity has been limited to a total of 640MB. However, Trans' 1GB memory upgrade module allows the main memory of the 800MHz, 933MHz, and 1GHz G4 iBooks to be upgraded to a maximum of 1.15GB (1152MB).

The 1GB memory modules operate at a clock rate of 133MHz and transmits data at 266Mbps.

The upgrade is $499. UK availability and pricing has yet to be confirmed.