The System comes pre-loaded with Windows Vista Basic- add in the Sony bloatware and it ran like a square wheel. I tried Windows 7 Ultimate, but it was still a little sluggish with Aero turned on.
I decided to go back to good ‘ole Windows XP, but Sony (as usual) does not offer drivers for XP; only Windows Vista and Windows 7.
Once I downgraded to XP, the unit works fairly well for a 1.33Ghz atom (and I have been able to overclock to 1.6Ghz with SetFSB). The screen is incredible and the wireless connectivity (WiFi, BlueTooth, EVDO, GSP) almost makes up for the meager 60GB (1.8” PATA) hard drive and the 2GB of RAM that is hard-soldered to the system board.
Even more important is the unit is small enough to fit in a jacket pocket and carry around- everwhere…
There is a tread on Pocketables on How to install XP on a Vaio P, but the links are to Japanese sites (i.e. no English version) to download the drivers and some others are now dead links.
Luckily, there is a ‘XP Downgrade’ folder on the Sony Vaio-Link FTP site that contains drivers for the Sony P series.