Based on my logs it looks like lots of people are ended up here looking for the Windows Hotfix for dual core processors (DasBlog has some good reporting built in so you can see where your visitors are coming from). I figured I would those people out by posting a link to the hotfix:
For people that have no idea what I am talking about you can check out KB896256. It appears this is for all multi-core CPUs, not just AMDs (I had this hotfix installed on my 4400+ AMD X2 but not on my laptop). For the AMD people there is a good forum post about how to install the X2 drivers and hotfix in the correct order at: http://www.xtremesystems.org/forums/showthread.php?t=81429.
There is one other Core Duo hotfix that I know of that affects the battery life when using USB2 devices. You can read the KB article and download the patch at: