The latest Power Mac, unveiled last month and now shipping in limited quantities, offers substantial architecture improvements over its predecessor that deliver exponential performance increases -- depending on the application being used or function performed. In addition to the use of dual dual-core G5 processors, the underlying upgrades are numerous, so I'll just list them here and then offer some commentary.

Processors

The dual-core technology now used in the US$3,299 top-end Power Mac G5 puts two processors on one silicon wafer, with each processor allocated 1MB of L2 cache. The result is twice the computing power in the same space. In a dual-processor, dual-core, machine (Apple refers to it as a quad-processor machine, although others call it a dual-dual), you've got four processors, four 128-bit velocity engines and eight graphics processing units. The speed increase on any computing work that can be broken up into parallel processing is exponential.

Real-world performance throttles back a bit due to disk I/O, but the increase in speed is immediately noticeable. I witnessed Final Cut Pro effects applied in real-time to eight video streams, and performance was barely affected. It must have something to do with the total RAM throughput being 8.5Gbit/sec. It's also worth noting that Mac OS X 10.4 and the G5 architecture can support up to 4TB of RAM. The machine isn't built to hold that much, since 99.9% of the user base couldn't afford it, but if you fill the 533-Mhz Double Data Rate 2 RAM Error Correction Code slots with the full 16GB on memory the box can currently hold, you've still got quite a screamer.

PCI Express Bus