[QuicksandWalker]

Did you ever find a solution to this?

I have even researched down to the thread stacks using Process Explorer and found the same culprit at the end of each stack "kernel32.dll!GetModuleFileNameA+0x1b4". For example:

ntoskrnl.exe!ExReleaseResourceLite+0x206
ntoskrnl.exe!CcUnpinDataForThread+0x338
ntoskrnl.exe!ZwYieldExecution+0xb78
ntdll.dll!KiFastSystemCallRet
RPCRT4.dll!I_RpcBCacheFree+0x5e3
RPCRT4.dll!I_RpcBCacheFree+0x405
RPCRT4.dll!I_RpcBCacheFree+0x5cb
kernel32.dll!GetModuleFileNameA+0x1b4

The command line to start this service is "C:\WINDOWS\System32\svchost.exe -k netsvcs".

The suspicious thing is, that even though there are dozens of instances of the svchost.exe running, only this one will occasionally peg my CPU at 95+%. And ONLY this one has more than a few services registered with it. It has 30 items in the Services list. And in the Threads tab (of Process Explorer) it will show 3 threads at a time jockying for CPU time and all three have the GetModuleFileNameA as the active thing on the stack. In fact, they all have the following 4 items on the top of the stack (bottom of list, visually):

RPCRT4.dll!I_RpcBCacheFree+0x5e3
RPCRT4.dll!I_RpcBCacheFree+0x405
RPCRT4.dll!I_RpcBCacheFree+0x5cb
kernel32.dll!GetModuleFileNameA+0x1b4

Does anyone know what these mean?

In the time it has taken to report this, it gave up and went back to normal operation. However, this pegging of the CPU can last for at least minutes. Killing the service will solve the problem and the PC still mostly works (no sound, etc.)