One of the major plagues of Tablet PC owners with more than 1GB of memory was an issue in hibernating where you have a good amount of memory used in your applications like OneNote, Tabbed pages in your favorite browser open, outlook, word, excel, mindmanager, etc open and want to resume again after turning your Tablet back on after travelling from one location to another. In the past you would receive an occasional error that your Tablet will not hibernate - "Insufficient System Resources Exist to Complete the API" error message in Windows XP with Service Pack 2, in Windows XP Tablet PC Edition 2005, or in Windows XP Media Center Edition 2005"
"A supported hotfix is now available from Microsoft, but it is only intended to correct the problem that is described in this article. Only apply it to systems that are experiencing this specific problem. This hotfix may receive additional testing. Therefore, if you are not severely affected by this problem, we recommend that you wait for the next Windows XP service pack that contains this hotfix.
To resolve this problem immediately, contact Microsoft Product Support Services to obtain the hotfix. For a complete list of Microsoft Product Support Services telephone numbers and information about support costs, visit the following Microsoft Web site:"
Link: http://support.microsoft.com/?kbid=909095
Well I applied the patch to several Tablets(1.256 GB) here at work 2 weeks ago via SUS/SMS and it seems to improve the performance and problems so far...
On my own personal Tablet PC loaded with 2GB of RAM, I have seen slight performance increases and stability, but still receive the same error when I have several windows/tabs open in IE, Maxthon, Mozilla or One Note. Hopefully the next hotfix or Vista will solve this problem...