Yes, but when the drive could reach around 40MB/s on a 4 year old Wintel machine and around 12MB/s on a brand new iMac (2006 24" at the time), there was something seriously wrong with the iMac's USB configuration.
This is partly true. But doesn't explaion why a 2002/2003 single core Athlon processor could run rings around an iMac with a faster Core2Due processor... Either Windows and Linux (the AMD was dual booting) were a lot less processor intensive than OS X, or Apple had deliberately slowed USB down.
Given that most reviews (from non-Mac magazines and websites) all marked the USB performance of these high priced machines as less than the cheapest Wintel box on the market, Apple either deliberately crippled USB on the first Intel motherboards or they b*lloxed up the design. Given Apple's usual attention to detail, and their licensing deals on Firewire, it makes more sense that they didn't suddenly want a Mac with a USB port which could achieve 70-80% the performance of a Firewire port.