svchost.exe 100% CPU?

[Niverive]

Why does svchost sometimes suddenly start taking up 100% CPU usuage for awhile then System Idle Process starts taking it up afterwards?

 

[Niverive]

Oh I just found out, I was playing FFXI at the time this happened, its an MMORPG for those who don't know, anyways I was with my real life friend who lives in the same apartment complex as me, his computer did the same exact thing at the same time his svchost.exe started eating his CPU for awhile, we both use the same internet provided by the complex, could this have anything to do with it?