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G5(1) A series of Macintosh desktop machines from Apple that use the 64-bit IBM PowerPC 970 CPU, a single-chip version of IBM's POWER4 family. Introduced in 2003, the G5 has a 1 GHz frontside bus and can access up to 8GB of memory. G5 models support the PCI-X bus and Serial ATA (SATA) interface for hard disks. The Power Mac G5 was the last Macintosh to use the PowerPC chips (see Mac Pro). See G4, Apple and POWER.
(2) The fifth generation of IBM's CMOS-based mainframes (Parallel Enterprise Servers). Introduced in 1998, G5 doubled the performance of G4 servers, debuted the FICON channel and added hardware-based Triple DES cryptography and numerous internal improvements. Memory was increased to 24GB. See G6, IBM mainframes and Parallel Enterprise Server and FICON.