I'm not sure what you mean, but check out
www.apple-history.com for information about these Macintoshes.
The slowest G3 would be:
Tied, Power Macintosh G3 (233/266/300/333 MHz) and the Power Macintosh G3 All-in-One (233/266 MHz). The tower was made in 1997 and the All-in-One was made in 1998.
Fastest G3:
The iMac G3 (summer 2001 model). Clocked at 500/600/700 MHz. Came in Graphite and Snow colors.
Slowest G4:
Tied, the Power Macintosh G4 (AGP Graphics). Came in a graphite color. Was clocked at 350/400/450/500 MHz. Also, the Power Macintosh G4 ("Yikes!"). Came in a graphite color. Was clocked at 350/400 MHz. Both were made in 1999.
Fastest G4:
Tied, the PowerBook G4 (1.67 GHz) and the PowerBook G4 (1.67 GHz with Dual Layer SuperDrive). The former was made in early 2005 and the latter was made in late 2005.
The slowest G5 would be:
Tied, the Power Macintosh G5 (original), was made in 2003. It came in 1.6/1.8/2x1.8/2x2.0 GHz models. Also, the iMac G5, the original "fat," iSight-less model. It was made in 2004 and shipped in 1.6/1.8 GHz versions.
The fastest G5 would be:
The Power Mac(intosh) G5 Quad, with dual processors at 2.0, 2.3 and 2.5 GHz, with the 2.5 GHz model having dual-core processors, to make four cores. This was made in late 2005. (There was also the dual-processor 2.7 GHz Power Mac, but the Quad 2.5 GHz model is much faster in terms of performance.)
Edit: Fixed.