Hot CPUI haven’t been able to watch online videos on my computer in over 2 years now. Not without excessive CPU use anyway. What happens is once a video starts playing the CPU load or use increases and stays fairly high for the duration. After a minute or two I can definitely hear my CPU fan getting louder. When I stop, close, or leave the video it gets quieter as it returns to normal, but it takes a few minutes to do so.

It all started one day after a FireFox update. So, naturally I figured it was somehow related. I spent hours searching for a solution over a two-year time span with no luck, and believe me there are numerous topics about high CPU use and FireFox.

It doesn’t matter if they are flash based .swf/.flv or html5, and resolution or size doesn’t matter either. Both high definition and smaller/lower/regular definition do it.

Every time I watch a video with FireFox CPU use is between 40-80% with an average of about 50-60% with a dual core CPU.

With Google Chrome it’s around 30-60% with an average of about 40-50%.

Internet Explorer is almost the same as Chrome.

The strange thing was if I watched a video stored on my computer with Microsoft Media Player the CPU load is just fine.

So, Firefox seemed to be the biggest problem, although the other browsers are still a little high and cause my fan to get noisy as well. They just take a little longer.

I tried all kinds of suggestions including the obvious. I updated my video/display drivers. I tried changing my video display settings to everything imaginable. I changed flash from use hardware acceleration to none or software, and did so in FireFox advanced settings too.

And, many … many other suggestions as well. I eventually gave up trying to fix it because nothing seemed to work, and I got tired of trying. I just told myself if I wanted to watch a video I would have to keep them short from now on.

Then one day I was researching Windows 10, and the free upgrade for Windows 7 and 8 users available until June 29th, 2016. (Be sure to do plenty of research before jumping into a Windows 10 upgrade!)

I came across someone asking about their video display drivers and compatibility with Windows 10. One thing lead to another and I landed on a page where someone was having a very similar high CPU use associated with videos.

They mentioned opening your computer case and cleaning the CPU fan and heat sink. I actually used to do this back in my computer building and fixing days every 1-3 years. Apparently 6 years have gone by since I bought my computer and I hadn’t realized it.

Long story short … I got a can of compressed air ($3-$6), blew the dust out, and problem solved. Last night was the first time I could watch a video without my CPU fan going crazy in over two years.

So, if you are having a similar problem with high CPU use when watching videos and you have tried just about everything that you can think of then it’s definitely worth checking for excessive dust build up especially on the CPU fan and heat sink.

Some computer cases are a real pain in the rump to open, and others are extremely easy. Hopefully yours is one of the easy ones.

Make sure your computer is powered off. Unplug all the cables and cords, and note where they go.

The big concern is the CPU fan and the heat sink under it which looks like metal fins. The metal fins can get so plugged up with thick dust that the fan barely cools them.

I wouldn’t take the fan off the heat sink because it’s difficult to get back on right if you don’t know what you are doing.

If yours appears to have excessive thick dust build up get yourself a can of compressed air. Take your computer case outside because it will make a big mess in your house. Then, blow out as much of the dust in and around the CPU fan as you can.

While you are at it blow everything else out too, but focus on the CPU area first.

If you find other heat sinks or video cards with fans or heat sinks be sure to blow them out too.

For those of you that are a little more adventurous like myself I also take the power supply out and carefully open it up and blow it out too. There is a fan inside that can get plugged up too. You want to be a little cautious with it because some of the components can hold electricity. So, don’t poke around and touch the internal parts with your fingers.

This may or may not solve excessive CPU use when watching videos, but it did for me. If nothing else it is definitely worth doing every couple of years anyway to help keep your computer running smooth, and to prolong its life. I guarantee your computer would thank you for doing so if it could.

This is the CPU fan/heat sink area: (CPU heat sink is very plugged with dust.)

CPU Fan and Heatsink area


This is the power supply area: (Lots of dust too!)

Power Supply area


Side Panel Vents: (Almost completely plugged.)

Side Vents


Dust Ball: (A little difficult to see, but this came out of the heat sink.)

Dust Ball


After: (Look how clean that is. Almost looks new now.)

All Clean

Total time will vary depending on experience and how easy your case is to open. I did mine including the power supply in less than an hour.

Be careful not to drag your feet on carpet so you don’t get static electricity build up. Ground yourself by touching something metal first. Watch out for little parts, capacitors, and such.

About: Jeremy LeSarge - AKA: Ray (233 Posts)

I am the site owner and administrator of I provide help and tips for Boonex Dolphin on the main part of this website where you will also find an assortment of other resources. Here, on the blog I write about a variety of topics surrounding WordPress, technology, social media/networking, SEO, and webmaster resources.