It was another engineering success, and a marketing failure. If only Intel had the same standards. Chip wise, it worked beautifully. It would require a stopwatch to notice any performance differences. In other words, an 80 MHz or 100 MHz 603 cost less than a 66 MHz 601, and offered more performance.
Big design wins.
Apples, Performas and Gotchas Apple was producing 601's in their business line, and so Apple used the first 603's in portables and low-end consumer desktops. They also wanted to update the design quickly, and get on the market. So Apple basically stuffed the 603 chip into the design that was supposed to support the 68040. These were econo-boxes. Again, the project was a success.