CPU under utilized even when system running slow.

For me it just worked to unplug and plug again the power cord. Some Dell computers decrease the system performance when they detect an "unknown" adapter. This may happen after an upgrade. Normally, it should work with this.

You really do not have to increase your CPU Usage which will slow it down to a huge extent. If you still want to do it, what? Run several useless processes unnecessarily! :P

Hi Ashwin,

Thanks for your reply.

That precisely is my problem, even if I run a lot of applications, the CPU utilization stops at a maximum of 37%, not 50%, not 38% but precisely at 37%. It seems like there is a lock active that does not allow the CPU to go beyond 0.91 GHz speed and 37%. This 37% turns into 25% and 0.60 GHz if I enable speed step through BIOS.

When I was using Vista, the CPU 'normally' ran at <5% (which it still does), but when I used the graphic intensive software (3Ds Max+VRay, AutoCAD, SketchUp+VRay) the CPU would jump to 100% while rendering and would finish it in 15mins. Now, when I do the same, CPU remains at 37% and the task takes around 35mins to finish up. This is a major degradation. Though for normal usage like web surfing or music, the CPU runs normally at <5%.

Since the maximum utilization percentage is a precise number, I figured there is something in the Win8 OS that limits it to that. If yes, how do I change it? Or is it that Win8 is not compatible with my processor?

You do not ever want to have 100% cpu usage. If you did, everything would be so slow that it would seem to be doing nothing. CPU utilization *should* be low. If your CPU utilization is running 25-37%, it's already on the high side, and that's likely why your machine is running slowly. For example, at the moment, I am running around 3-5%.

Thanks Ken for your answer.

My machine runs at 3-5% during normal usage like when I'm using MS Office or Explorer. There are no issues with the startup too. The problem comes when I use a program that require a high processing power. While rendering an image in 3Ds Max or Sketchup, you would normally expect the CPU to jump at 100% till the rendering is finished. This is how it worked with Vista.

While in Win8, the CPU stops at exactly 37%, the rendering takes more than double the time it should normally take. I have an updated BIOS and drivers too are updated. I hoped that there would be some tweak that could iron this out.

I have a Dell Precision M4300 notebook with Intel Core2 Duo T8300 (2.40GHz) CPU. Recently I upgraded to Windows 8 pro from Vista Business. I use a lot of graphics intensive applications and I noticed a drop in performance. The baffling part is that CPU never shows a 100% usage in Task Manager performance monitor.

The CPU shows a 25% maximum utilization with speed step on and 37% with speed step off. While with the previous windows installation, it showed 100% utilization while these programs ran. Even the system performance rating has dropped from 4.4 to 3.1 (2.4 with speed-step enabled).

Why is the CPU under-utilized even while running resource intensive applications? How can I use 100% of my CPU?

I have uploaded some screen shots herefor more details.

You do not ever want to have 100% cpu usage. If you did, everything would be so slow that it would seem to be doing nothing. CPU utilization *should* be low. If your CPU utilization is running 25-37%, it's already on the high side, and that's likely why your machine is running slowly. For example, at the moment, I am running around 3-5%.

Just a guess as to what's making it run slowly, but malware infection is very common these days. Your first step in troubleshooting should be to make sure you are not infected.

Hi ad,

Thank you for posting your question in the Microsoft Community.

The first thing I want to tell you that having a low CPU Usage is a goodthing i.e. preferably below 50%. Having a high CPU Usage shows that your computer is running several processes using up a lot of usage which corresponds to those processes being useless or malicious.

I suspect that you are confused between CPU Usage and performance.

An increased CPU Usage does not mean having a resourceful use of the Computer. Performance is rather high when the CPU Usage is low.

You really do not have to increase your CPU Usage which will slow it down to a huge extent. If you still want to do it, what? Run several useless processes unnecessarily! :P

If you want to increase your system performance, in the task manager search for Processes and disable those which are not needed or appear malicious.

If your PC is slow right from start up, you can speed it up by disabling start up programs and applications.

To do this,

1. Press Windows+ R or search for Run on the start screen.
2. Type in 'msconfig.exe' without the quotes and press ok or enter.
3. In the start up tab, search for programs which are not needed by you and disable them(Caution!).
4. To disable applications, type in the following in the Run prompt without the quotes, replacing <abc> with your user profile folder name.

%systemdrive%\Users&lt;abc*>*\AppData\Roaming\Microsoft\Windows\Start Menu\Programs\Startup 5. Delete any unrequired shortcuts.

Ashwin