Why is Windows 7 throttling my laptop CPU?

Question

I have been dealing with this problem for months.

The Computer

• Model: Dell XPS M1330 (specs found here; I have the full 4GB of RAM)
• Age: 3+ years
• OS: Windows 7 Professional x64

Problem Investigation

One day I noticed that my computer was intermittently experiencing major slowdowns. It was to the point where there are sometimes several seconds of delay between me pressing a key and the character appearing on the screen. At first I thought that a Chrome update was causing the browser to eat all of my CPU, but eventually I figured out it was happening even when Chrome wasn't open. Finally I got the bright idea to use the Resource Monitor and noticed that Windows was routinely throttling my CPU to 25%.

What I've Tried

• I checked the health of my disk drive and ran pretty much every system maintenance utility that Windows ships with and the problem persisted.
• I have systematically played with power settings
• After some Google searching, I found out that the most common reason for this is overheating. So I did the following:
  • Had all my fans cleaned
  • Had the thermal paste on the heatsinks replaced
  • Used SpeedFan to confirm that temperatures are all normal (except for the GPU, which is apparently normal for this model).

The problem persists. In fact, sometimes it's even worse now. If I really need to I'll suck it up and buy a new one, but I would like advice on how to proceed from here.

Answer 1

Check that your power supply is rated for that laptop. Dell has different laptop power supplies which, though they have the same voltage, not all provides enough current for the higher end laptops running at full power. The laptop handles being plugged to one of these by throttling the CPU when it detects the under powered supply.

It's an easy situation to test for, set a power plan that has minimum processor state at 100% both when on battery and on AC, have the Resource monitor running, confirm that the CPU is throttled despite the power plan setting, then unplug the power connector. If the CPU throttles up to 100%, it's the power supply that caused it and you should get one rated for the laptop's actual current requirement.

Answer 2

If what you're looking at is the "Maximum Frequency" value in Resource Monitor, that it only partially controlled by power management and is more likely only an indication of your issue, not the cause.

Anytime your CPU pegs at 100% usage, regardless of the Maximum Frequency at that moment, you have programs that must be investigated.

The list of things that adjust your CPU's Maximum Frequency are rather long and vary with each CPU.

• Windows Power Management
• Intel SpeedStep or other on-demand frequency management systems that allow or underclocking or overclocking
• What ever cooling management your processor uses

You can adjust the Windows Power Management, and to a certain extent you can modify the CPU's internal throttling in the BIOS.

But more important than that, you need to see what processes are running the CPU at full throttle.

UPDATE

Chrome likes to use a lot of CPU, especially when it's running anything utilizing Flash. Well, not just Chrome. Just about everything likes using a lot of CPU when trying to get Flash to do something for it (I can't believe I just agreed with Jobs).

Less fortunately, there's not a lot you can do about it. Chrome puts a priority on the user experience, which means using all the resources it can get it's 20 grubby processes on.

General tips on keeping your computer running at peak performance:

Get CCleaner from Piriform (http://www.piriform.com/ccleaner/download). Use it to clean your system temp and unnecessary files. It has a function for compressing the Chrome databases as well. Use it.

Then use it to check and clean your registry (it allows you to backup all changes prior to actually making them, DO THIS). This isn't a silver bullet, it won't fix every problem with your computer. But the CCleaner reg cleaner is the one I've trusted for the last 3 years (since finally leaving the XP-compatible Regclean app from Microsoft). I have not yet found a case where it has messed up an app, driver, or OS, but run the backup anyways.

Then in the Tools section, use the Startup tool to remove anything that you know you don't need starting up on system load. Leave anything related to antivirus or computer security apps, everything else can go if you know it has a valid reason for being run when your computer first starts up.

If you're really capable, you could use Autoruns to check through your system services and clean those out and remove references to missing driver files. Every little bit helps, though in Windows 7 I've found most services only run if they're really needed, unlike XP's "hey it's a service, let's run it" mentality.

Answer 3

I too have problems with a desktop in that windows 7 ignores or does not honor my min-max 100% cpu setting under power management.

Some people have claimed that their ATI catalyst "Ati External Event Utility/Ati Hotkey Polling" service is the culprit. This is not the case on my machine, but you might look into this.

Mine is a Dell machine as well, and there is no BIOS setting exposed WRT power management and EIST

Answer 4

You should run thorough anti-virus, malware/spyware/adware scans to remove any rouge processes which could be causing this problem. Malwarebytes and Spybot Search & Destroy are good tools.

Here is a link to a Superuser wiki with some additional useful information.