Computer Performance: Impact of Power Settings (Windows)

Modern day PC’s have an abundance of settings to help us save on power usage.  This is great by design as less power consumption equals lower power bills.  However, like everything there are positives and negatives.  I have run into instances where these settings have actually hindered my PC’s performance to the point of frustration only to find out it’s these software settings instead of the hardware causing problems.

Windows Power Settings:

Windows offers plenty of options for customizing power usage based on the concept of power plans.  In Windows 7, they are located under Control Panel -> System and Security -> Power Options. There are three default plans available in Windows from Microsoft(although others may be included from your PC manufacturer):

  • Power Saver
  • Balanced (Default)
  • High Performance

Each of these is pretty self explanatory in the fact that they describe how much power they will each use.  You can expect slower performance with Power Saver as it slows components of your machine down to use less power.  Balanced should give you expected performance while saving some power and High Performance should have all components functioning at their full potential at any given time.

Balanced Plan: Sluggish Performance

I never thought I would need to adjust power settings on a desktop PC.  However I quickly discovered that Windows aggressively throttles power even on a balanced setting.  How could this be?

By default anything less than High Performance will have Windows throttle your CPU and other components and give them needed power(and thus performance) when it thinks it needs to.  This is usually ok and provides expected performance for light tasks such as web browsing, light photo editing and other non-intensive tasks.  I had also initially thought that it would be intelligent enough to give additional power for an extended period of heavier use.  However, this turned out to be incorrect.

When I first encountered a performance problem  it was after building a new PC where I upgraded from an old Intel Core 2 Duo (dual core) to a newer AMD Phenom II x4 (quad core).  All other parts remained constant(except for the motherboard as AMD and Intel chips have different connectors/sockets).  After the upgrade I noticed that while playing games my frame rate stuttered and overall performance was slow.

Now my new processor did feature a new power saving feature, which I had noticed before.  My CPU monitor gadget in Windows Vista showed that the frequency was 800MHz (0.8GHz) instead of the 3.5Ghz advertised except for when more power was needed, and then it was scale up appropriately to its full speed.  I had witnessed this previously while doing general tasks such as web browsing and light photo editing without much thought as everything seemed to run as fast as I remembered.  However, once playing a game I noticed the frequency was completely erratic.  The constant changing demands on the system were causing the power saving feature to ramp up and throttle the CPU every time it hit anything intensive.  This constant change was the cause of my horrible performance.  There was a delay in how fast Windows could increase power before the need was over and thus tried to limit it again.

After discovering this I researched how to disable it and quickly changed my power plan to high performance to alleviate the issue which worked like a charm.  Later after doing more research I was able to change the balanced plans settings to get the benefits of energy savings on my other hardware while ensuring smooth CPU performance.  This can be done by editing the power plans advanced settings and changing the Processor power management options Minimum and Maximum processor state values.  A very technical description of these options can be found on here.

Why is this important?

Ok, so you may be asking why is this so important?  Why should power plans be anything I ever care about managing?  Perhaps you don’t play games or never have experienced slow or choppy performance on your current PC?  Even if that is so, there are numerous times you may want to keep this in mind as a potential answer to a future PC problem.

Suppose you have an older PC that just doesn’t seem to cut it anymore and you are begrudgingly thinking about buying a new one.  Changing the power plan for it may give some life back depending on the software you have installed and what you use your machine for.

Another example would be that you purchased a new high performance PC and it seems to perform worse than your previous one in gaming or other intensive tasks.  You can quickly and easily change the power setting to see if there are immediate results.  I have read numerous times online where people are upset about their new PC with an issue that sounds like it is exactly this problem.

How to Check CPU Frequency

One way to check the CPU frequency is with gadgets for Windows which is how I originally discovered and fixed my problem.  However Microsoft has found vulnerabilities in the gadget platform in Vista/7/8 and since discontinued them.  You can still find them available online, though they are to be used at your own risk.

An alternative method to gadgets to check your CPU’s frequency would be to use any CPU monitoring software.  For hardware monitoring software, I use CPU-Z and HWMonitor by CPUID and CPU-Z can show you your current CPU clock speed/frequency by looking at the Core Speed value.

If you know of any other alternatives to determining clock speed or tips for better performance with increased power management I would love to hear about them!  Please share any thoughts or questions below!

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