The problem is the nature of Svchost as it is a Service Host and is used by other applications, so for the most part it isn't actually svchost that is using the CPU but something using it. The windows update is a major hog of svchost as that is what it uses to connect to get your updates.
Some report that if they switch from the newer Microsoft Update back to Windows Update, plus manually using Office Update, the issue goes away. To flip back to WU from MU, just follow the instructions in KB 901037. Just remember, if you do this, you'll have to manually go to Office Update to get patches on Patch Tuesday.
I'll update Patch Watch readers in future editions with any new information on this very vexing issue.
USEFUL - Find out what is using the SVCHOST Service.
Windows Start, Run, type (or copy and paste) "cmd.exe /k tasklist /svc > c:\tasklist.txt" without the quotes - this opens a command window and runs the tasklist for services, the > c:\tasklist.txt outputs the results to the file and location given:
svchost.exe 1020 DcomLaunch, TermService
svchost.exe 1080 RpcSs
svchost.exe 1108 AudioSrv, BITS, CryptSvc, dmserver,
EventSystem, helpsvc, HidServ, Netman, Nla,
RasMan, Schedule, SENS, SharedAccess,
ShellHWDetection, TapiSrv, Themes, winmgmt,
wscsvc, wuauserv
So first having identified in task manager, which PID (Process Identifier) copy of svchost.exe is using the high CPU% and check that against the above data you get having run the analysis.
