It looks like these are the services hiding behind that svchost process:
svchost.exe 980 AudioEndpointBuilder, EMDMgmt, hidserv,
Netman, PcaSvc, SysMain,
TabletInputService, TrkWks, UxSms,
WdiSystemHost, Wlansvc, WPDBusEnum, wudfsvc
After a bit of research with help from Google, it looks to me like SysMain aka SuperFetch is the most likely culprit.
As I mentioned it seems to have been chewing a lot on particularly those large game data files (now I've noticed that the same goes for a lot of smaller ones as well, I just never really noticed those before as they obviously don't result in 5-10 minutes of hard disk trashing), and I guess that makes sense as I've been playing those games a lot the last few days, making those files prime candidates for whatever kind of optimization it is SuperFetch does.
Well, I guess at most half an hour of wild hard disk trashing a day is well worth listening to, if SuperFetch actually provides a noticable performance increase?
Anyone running Vista with SuperFetch disabled? I've got 8 GB RAM - not sure if that makes the service less useful than on systems with less memory?
Edit: Sounds like turning it off could actually be a good thing according to some of the comments on this page -
http://www.howtogeek.com/howto/windo...windows-vista/
I'll give it a shot, but obviously any additional input on this topic is welcome.