14 DAY TRIAL // An Intel Pentium M 740 processor at 1.7 Ghz (479 socket) has been tested by PCStats and it seems that a Sempron 3600+ is better. They were both tested with SYSmark 2004, Business Winstone 2004, Content Creation 2004m SiSoft Sandra 2005, Maya Render Test, Super Pi 1.1 and PCMark 05. (In PCMark 05, the overall score is not so great for the Pentium M, as there are many factors that come into play, like the CPU power and single/dual channel memory controller).
The Pentium M was Intel's first mobile processor, designed from ground up. Previously, mobile processor lines were just low power versions of the desktop variety... to disastrous results. When energy consumption is not an issue, the Pentium 4 is perfectly adequate for desktops, however to stick it into a notebook is akin to running a hot plate off your laptop battery.
While the Pentium M processor is compatible with the Pentium 4 bus, the CPU uses the Socket 479 form factor, so there is no inter-compatibility. If you'd like to run a Pentium M processor on a desktop system, you'll have to get yourself a Socket 479 motherboard or small form-factor PC system.
According to the results, the Pentium M fails (obviously) to compete with all the dual-core out there and even with a Sempron 3600+ (although it did better in a few tests, the overall score is a disaster).
But, if you want a decent and quiet processor, at a medium price (203$), it may be the perfect choice for you.