PowerPC 7447 and 7457
The PowerPC 7447 "Apollo 7" is slightly improved from the 7450/55, it has a 512 KiB on-chip L2 cache and was manufactured in a 130 nm process with SOI, hence drawing less power. It has 58 million transistors. With the 7447A, which introduced an integrated thermal diode as well as DFS (dynamic frequency scaling) Freescale was able to reach a slightly higher clock. The 7457 has an additional L3 cache interface. However, its frequency scaling stagnated when Apple chose to use the 7447 instead of the L3 cache-enabled 7455 they used before.
The only companies that offer the 7457 in the form of upgrades for the Power Mac G4 and Power Mac G4 Cube are Giga Designs, Sonnet Technology, Daystar Technology (they use the 7457 only for iMac G4 upgrades) and PowerLogix. The Pegasos computer platform from Genesi also uses 7447 in its Pegasos-II/G4.
Read more about this topic: PowerPC G4