Over the years we've had to deal with antivirus programs bringing PCs to a screeching halt as they perform a "background" scan. At my last job, it was a morning tradition to plug in the laptop, boot it and go for a walk while McAfee did the daily scan that reduced my laptop to the speed of a 386.

It's one reason why I use ESET's NOD32. The program is written in assembly and runs incredibly fast. I can perform a full, in-depth virus scan while playing 'Call of Duty' and neither the game nor the scan is impacted.

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At some point, Symantec and McAfee got a clue and made their software far less obnoxious so they don't kill your computer. They had to. Surveys found people were uninstalling antivirus programs because they were so obnoxious, and leaving PCs exposed in the process.

But not every ill-behaved program has been tamed. There are still apps that can choke a modern PC, even a gaming rig as powerful as mine.

I run a very nifty desktop utility called Rainmeter on my PC that I heartily recommend to anyone who wants to keep an eye on their system. One of its main features is it has skins that can monitor your system activity. Thanks to my numerous meters, I see all CPU, disk, memory and network activity in real time.

Occasionally, I would look over at the CPU meters and notice something wrong. There are eight total meters, since I have a quad-core PC with hyperthreading. And four of the eight, the cores, would often be running very high, like 25-35%.

Then I looked at the C: drive meter. It is a circle split down the middle, with the right half lighting up to indicate a read and the left half lighting up for write activity. The C: drive was flashing a fair amount of activity considering I had nothing loaded save Outlook and Word, plus a few background apps.

At the time, I didn't have a Rainmeter skin that lists the top processes by CPU and memory. So instead, I went into the Task Manager, and under Performance selected the Resource Monitor. Under the Processes tab, the culprit showed its face immediately: AppleMobileDeviceService.exe. It was consuming a ridiculous amount of threads and CPU cycles.

The problem came and went. Sometimes it would disappear for weeks at a time, then come back. Finally, I decided to look into it. A little investigation revealed everything I needed to know. This app is a service installed by iTunes and used for iPhone and Apple TV only. iPad and iPod users have no need for it. It installs as a Windows service, turns itself on as default, and is practically unkillable. I've tried to disable it in the Process Window, but no luck. The only way to turn it off is to go into Windows Services and turn off the service.

There’s just one problem. I use an iPhone. I can't disable it. But doing so for a little while dropped the CPU meters to nothing. So I now have more motivation to migrate to a new phone beyond just having one with a larger screen.

This problem has been known for years. AppleMobileDeviceService.exe has been in iTunes since version 7.3. People complained on the Apple boards more than two years ago that it was consuming up to 50% of CPU cycles, and thus far it's as bad as it always has been. Mind you, Mac users aren't complaining. Just Windows users.

So, if you are using iTunes on a PC and have no intention of connecting an iPhone to the PC in any way, go into Services and disable AppleMobileDeviceService.exe. You'll be glad you did.

Late note to the Slashdotters: I use the latest version of iTunes, 11.0.2.26.