Tim Barcz

Optimizing My Old Computer - Part II - Does Dust Affect the System?

In my introductory post in this series, I expressed my desire to fix up my old computer an get it running in tip-top shape.  I was curious in cleaning up my PC, how much dust and cabling played into the interior head of a system.  For those of you unlucky souls who are the "computer guy" in your family you know you've seen some serious dust bunnies in computers.  I buy canned air and on occassion will clean out my system.  Is that doing any good?  Let's find out.

In thinking about this beforehand I had decided that I wanted to be somewhat scientific in my approach to determine how much dust played in temperature of the computer.  As Jeff said in his recent post on overclocking your computer:

"CPU temperatures are the enemy of speed-- all other things being equal, the higher the CPU temperature, the less likely it is your system will be stable. (This is also why extreme overclockers use water cooling and liquid nitrogen.) That's one reason why we have a fancy aftermarket CPU cooler." - Jeff Atwood

Dusty Interior

If you remember back to my last post, I mentioned that my current system sits with the side of the case open.  In peeking around my case I noticed that there was a lot of dust. 

Gathering Data

Setting the Baseline (Test #1)

As you can see from the pictures, my CPU is dusty.  I decided to get a baseline temperature before goign to town cleaning using PC Alert (note that CoreTemp, as recommended Jeff didn't work in my AMD).  Here's the baseline:

• CPU Temperature - 45-53 degrees
  
• System Temperature - 41 degrees

Load Testing the Baseline (Test #2)

Next, I ran the Prime95 torture test on my PC for about 10 minutes.  I watched the temperatures rise to the following:

• CPU Temperature - 60-64 degrees
  
• System Temperature - 45-46 degrees
• Observations - much hotter CPU and system temperatures.
  

Load Testing the Baseline + Fan (Test #3)

I wanted to see what the effect of a house fan blowing directly onto the case would be.  I placed a small house fan directly blowing on the motherboard and ran the torture test again, this time for only 5 minutes.  I only ran the test for 5 minutes because the impact of the fan was obvious nearly immediately.  The results were:

• CPU Temperature - 51-55 degrees
  
• System Temperature - 30 degrees
• Observations - The CPU still remains warmer than baseline by a significant margin.  What amazed me though was the system temperature dropping to 30 degrees.

Baseline with the Case Closed (Test #4)

I mentioned in my last post that I leave the case open to facilitate air movement and cooling.  I thought I would test to see how hot the system gets.  To establish a temperature to compare with the original, I let the computer sit idle and cool down before putting the case back together.  I was astonished by what I saw.  When I closed up the case entirely in the still dusty system I saw the following:

• CPU Temperature - 50-53 degrees
  
• System Temperature - 36 degrees
• Observations - The CPU temp is nearly the same, however the system temp dropped by 13%.  This was shocking to me.  In the years that I've left my case open "helping" my system, I was actually putting more stress on the system in terms of heat.  If you take nothing else away from this article, please get this point; That closing your case actually helps airflow and thus keeps your PC cooler.

Making Some Changes

Having satisfied myself that I had gathered enough points of data, I set out to cleaning the PC.  I was going to pay attention to three very specific things.

• Dust

The dust in the system was bad.  I remove dust from components.  I remove parts/components where necessary to facilitate better cleaning. I even cleaned the heatsink.

• Cable routing

Gamers swear by this but I often wonder how much it helps.  I thought while I'm in the system, it wouldn't hurt to clean up some cables. 

• Routed longer cables along the edge of the case and secured with electrical tape. 
  
• Used 8" cable ties to cinch up the the main strands of cables that were hovering above the CPU. 
  
• Removed unneccesary cables/wires such as my Audigy Remote control cable which I never use.
  

• CPU Cooling

To facilitate cooling I reapplied a silicone thermal compound the heatsink.

Running the tests again

Cleaned System with the Case Closed (Test #6)

Again, I let my PC cool and get back to a normal temperature.  With my desktop up and minimal programs running I watched the temperature.  Not surprisingly I saw a huge drop.

• CPU Temperature - 39 degree
  
• System Temperature - 31 degrees
  
• Observations - Simply by cleaning the dust, routing some cables and reapplying thermal paste I saw roughly a 22% drop in CPU temperature and a 21% drop in system temperature over the original, open-case dusty numbers.

Cleaned System with the Case Closed Under Load (Test #7)

The final test, where the rubber meets the road.  Here I ran Prime95 for lengthy period just to make sure the system didn't revert back to higher temperatures.  After the reductions in temperature, there was no surprise here:

• CPU Temperature - 47-49 degree
  
• System Temperature - 35-36 degrees
  
• Observations - The CPU is now operating cooler under the "torture test" than it previously was in test #1 when it was simply idling.  The CPU temperature is 23% lower and the system temp is 24% lower the than the same test performed in test #2.  This test was the greatest increase in cooling among any of the tests.