MacSpeedZone tackles the question “Does The PowerBook’s Extra Cache And Different Graphics Card Make A Difference? – A Performance Report”

Statistically these two machines are fairly similar. Both have an 800 MHz G4 processor with 256K of L2 cache running at full processor speed. However the PowerBook also has a L3 cache which sits between the memory of the machine and the processor. This extra cache provides the processor fast access to frequently used data, and so provides more efficient processing overall.

The benefits of this cache and the fact that the PowerBook has a 133 MHz System Bus, has an impact on the scores you’ll see below. The PowerBook, in most processing intensive tasks, turned in from 10 – 20% speed improvement over the cache-less iMac.