Dear Microsoft,
This is quite remarkable. We are now in March 2016 and the first post is from December 2012. About 2000 other people seemed to have had the same problem on this forum and the first answer apparently did not solve the problem for most customers.
I have the exact same problem with a clean installation of Windows 8. The Service Host process is consuming approximately 1 GB of RAM and practically brings the computer to a standstill. I have not installed a single piece of third-party software and the computer came with a pre-installed version of Windows 8. I have since installed the operating system twice manually, but the very same thing happens every time.
I have tried installing all Windows updates, I have tried not installing any updates. I have thrown off all the pre-installed Toshiba system software - to no avail. The suggestions other users gave here on the forum also did not work for me. All I can do is to kill the process manually and then continue working. However, at any moment Windows will automatically start the process again and it will immediately go back to its high usage of memory.
Is there any solution to this?
I do not even expect an answer from Microsoft really. But if for some reason I do get a response, please do not tell me to upgrade to Windows 10. Windows 8 is supposed to be a fully functional operating system on its own, is it not?