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I'm trying to fix a few low end single core desktops running Vista. In normal use they're fast enough not to be a problem. The issue is that because these machines are only on when being used, primarily for school work, windowsupdate begins installing patches it launches TrustedInstaller which in turn hogs 100% of the CPU and renders the machines all but unusable for however long it takes to patch them.

How can I limit the amount of CPU time TrustedInstaller.exe can have?

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I found a utility that's designed to cap a processes CPU share. Unfortunately while it works fine on processes I started it can't lock onto trusted installer (running in kernel mode?). – Dan Neely Mar 25 '10 at 1:37
I tested win7 on one of the systems, it's version of Trusted Installer was much better behaved. If nothing else works I might end up recomending for an OS upgrade. – Dan Neely Mar 25 '10 at 13:00
up vote 0 down vote accepted

When a process is already running, you can call the task manager (or Process Explorer) to lower its priority to idle. This should normally make this process no longer hog 100% of CPU, as it should be the last one in the priority of processes.

However, I don't know how to force a priority for a particular process, for the next times it opens. Maybe someone else will have a way to do that.

Edit: This other question seems to have a good answer on the way to save a priority for a particular process.

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First thing I tried. I don't know why, but even at the lowest priority it was still devouring the CPU and leaving the rest of the system lagged to unusability. – Dan Neely Mar 25 '10 at 1:35

I find Process Hacker 2 useful for exactly that. It allows you to alter process priorities (including those of TrustedInstaller.exe) and save the CPU priority setting so it is always used so long as the Process Hacker program is running.

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Although Process Hacker allows you to change a process priority it does not allow you to limit the cpu share ... – DavidPostill Aug 24 '14 at 20:03

Edit: I thought you need to limit cpu usage while updating. In that case you may use ThrottleStop, set Clock Modulation and Chipset Clock Mod below 50, then set multiplier to the lowest value.

In your case, you may use Battle Encoder Shirase (BES).

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How is that supposed to help? Making the CPU slower won’t lower a specific application’s process priority. On the contrary, it will make everything even slower. If you want to recommend the second tool, edit your answer again and read up on how to recommend software. – Daniel B Jan 3 at 22:27

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