Sonnet has announced its first dual processor upgrade for G4 PowerMacs. The Encore/ST G4 Duet includes two 500MHz processors and works with any G4 with an AGP graphics port. Each chip includes 1MB of 250MHz backside cache. Upgrading using the card allows the machine to run all Mac OSs from 8.6 to OS X with full symmetrical multiprocessing. Setting up the card requires no software installation and a minimum of configuration, according to Sonnet. All that needs to installed along with the board is a heat sink adapter to cool both processors. The upgrade cards will ship in February for an as yet undisclosed price – though in the US they will ship for $999.95 (around £680).