One review shows the cpu being a 1.6 GHz Intel Pentium M 730 (Sonoma), 533MHz FSB and PCIe x16 chipset. If there are extra dimms slots for expansion you shouldn't see any problem adding in additional DDR2 400 memory of the same type.
A few of the older versions of 9x Windows saw limitations when going over 512mb of memory. That won't have any bearing on the cpu.