While the Samsung Q1 UMPC only has a 900 MHz processor and 1GB RAM, Kevin Tofel has been able to get Vista running on it quite well with only a couple of limitations. If you want to try this out, create a partition first and test it before leaping into a full install.
Fellow MobileTechRoundup podcast co-host Kevin Tofel is the guy who swayed me to purchase the Samsung Q1 UMPC a few months ago and he can be found pushing the limits of the device all the time. His latest escapade has me quite excited as Vista is running on his Q1 with something like 95% functionality. Kevin was able to get the touch screen working along with both the WiFi and Bluetooth radios and it sounds like everything is running quite well. There are a couple of registry hacks you have to make to tweak the drivers into working properly, but Kevin did all the work (with some help from readers) and has it documented in his post. I understand he also plans to make a video of Vista on the Q1 so stay tuned for that too. The floating TIP isn't working due to the touch screen interface on the Q1. Also, the Samsung specific drivers/utilities for screen rotation and resolution switching and the Samsung pop-up control menu aren't working and most likely require an update from Samsung themselves. It is cool to see Vista running on a device like the Samsung Q1 as it gives hope for those that may not have the most powerful PC in their hands at this time.