actually not easy to find at all. Not a word on Seagate website, not a word on siliconimage.com. When I dived deep into my registry I found
HKLM\SYSTEM\CurrentControlSet\Services\si3112\ProblemDevices
A lot of string values, all Seagate drive model numbers, all with data Mod15Write.
After searching Google for Mod15Write I found a lot of forum sites, mainly Linux developers, discussing the mod15write problem in such programmers lingo that it still took me a lot of time before I got the picture.
see for example
http://home-tj.org/wiki/index.php/Sil_m15w which is in relatively clear simple lingo.
So to let this forum be the first to have the whole picture for non-linux users in plain English (with a Dutch accent)
Lots of Seagate disks are not 100% compatible with si3112 controllers. The results can be system hangups and bad performance. One workaround is adding your drive type to the list in the above registry key. This prevents system hangups but at a cost: even worse performance.
The other workaround is either another controller or another drive.
The brands using si3112 chips AFAIK are ATI, Dell, Gigabyte, IBM, Logitech, MSI, NEC, Sitecom, Sony, System Talks, Sweex and even Intel.
Not happy and very curious how these companies have been able to hide this fact for so long.