Sonnet Technologies has announced its new Encore/ZIF (Zero Insertion Force) G4 1.0 GHz upgrade, the fastest processor upgrade yet for beige G3 Power Macs.

The upgrade uses the 745X series Motorola G4 chips, has a 256K L2 and 1MB L3 cache, and improves the processor performance of the beige G3s by a factor of ten.

Sonnet president and CEO Robert Farnsworth said: "Sonnet is very excited to announce this significant speed bump to the Encore/ZIF line. The Encore/ZIF will enable an entire generation of Macs to attain modern levels of performance."

Announcements of additional speeds and further compatibility with Blue & White and G4 PCI Graphics systems are expected in the coming weeks.

The upgrade supports Mac OS 8.6 through OS X. It costs £479 (ex. VAT) and ships in May.