Troubleshooting Slowness, Buffering, Stopping, or Stuttering in TestOut Videos

Tanner -

This article is focused toward troubleshooting TestOut videos. See this article for troubleshooting slow or unresponsive lab simulations.

Table of Contents:

  1. Quick Troubleshooting Ideas
  2. How TestOut’s Videos Work
  3. How to Find your Internet Speed
  4. Troubleshooting Internet Speed-Related Issues
  5. Troubleshooting Computer-Related Video Issues
  6. Other Troubleshooting Ideas

1. Quick Troubleshooting Ideas:

  • Restart your computer
  • Reset your router
  • Make sure you have an internet speed of at least 3.6 Mbps per user (Test your speed at    This is, generally, the single most important factor in having a smooth experience while viewing our videos.
  • Try the videos in a different browser, because the browsers can perform very differently

2. How TestOut’s Videos Work

Our videos stream from and The videos are, by default, 720p quality .mp4 files with an H.264 encoding that are streamed as HTML5 video and played by your internet browser. A typical video can be 20MB - 80 MB in size. Our videos support mono and stereo audio only, so custom audio managers and speaker setups should ensure that they are not using surround sound in order to hear the audio.

We contract Microsoft to use Verizon POP servers to deliver our content anywhere in the world with speed and efficiency. Due to the way it is set up, it is very uncommon for any slowness to be caused by too much demand on the servers. 

3. How to Find your Internet Speed

We officially require at least 3.6 Mbps internet download speed but we have found that most videos stream fine at 3 Mbps. At around 2.5 Mbps some momentary buffering may be noticed. Approaching 2Mbps or less, stopping, stalling, and buffering can be a frequent occurrence.

To check internet speeds, we recommend freshly restarting the computer, resetting your router, and turning off any other devices that use your internet connection to reduce the possibility of interfering factors. Then navigate to (chosen for its simplicity and acceptable accuracy). will automatically begin to run its test and tell you your download speed. If you suspect the result you see is inaccurate, reload the test once or twice. If you see Kbps instead of Mbps then your internet speed is inadequate. 1000 Kbps = 1 Mbps.

4. Troubleshooting Internet Speed-Related Issues

If you find that your internet speed is below our minimum requirements, here are some ideas on what you can do about it.

a. Contact your internet service provider (ISP) and ask what speed you are paying for. If you are paying for speeds that exceed 3.6 Mbps, but your results indicate that you are receiving considerably less than that, then you should ask your ISP to help you troubleshoot the issue further.

b. If you are paying for an internet speed that is slower than 3.6 Mbps, then consider upgrading your Internet plan or using a faster internet connection at another location, such as at a public hotspot, your school, or the public library.

c. Do what you can on your end. Limit the number of devices that are connected to the internet, try connecting your computer directly to the router with an Ethernet cord, or test on another computer and/or internet connection.

 5. Troubleshooting Computer-Related Video Issues

If you still can’t play the videos without them stuttering, stopping, or buffering, even after ensuring that your internet speed is adequate, then the problem may be on your computer’s end. Your computer needs to be able to receive the video from the internet through its network card, interpret and open it with browser and CPU, and play and display it with the video card/chip and monitor. Many things could interfere.


1. Ensure that your network and display adapters have updated drivers.

In Windows, open the Device Manager and expand the network and display adapters sections, right click on the adapter and click Update Driver Software.  

2. Try toggling on or off your browser's hardware acceleration setting. Having it set to on is the typically preferred default, but we have seen strange video problems be solved by toggling the setting. In Google Chrome, this can be toggled by going to chrome://settings/ , clicking "Advanced" at the bottom of the page, then scrolling down to the "System" area and switching the "Use hardware acceleration when available" setting on or off.


3. Close any programs that don’t need to be running. Some programs and browser extensions, add-ons, toolbars, or plugins can slow you down and eat up your computer’s resources. Others automatically start in the background when you start your computer. Before you restart your computer, try turning off some of the programs that don’t need to start with your computer or browser. This will free up the computer’s resources to focus on TestOut. Consider doing the following things (Google how to do them if you don’t know):

Disable unneeded start up programs

Helpful article:

Disable unneeded browser extensions, add-ons, toolbars, or plugins (keep Microsoft Silverlight)

Helpful Article:

4. Malware can affect your experience with our software. Look through your list of programs and browser extensions. Look for tool bars that you didn’t intentionally install and other items. Pay attention to whether you get redirected to different sites than you entered or if pop-up windows constantly come up. If you notice anything out of place, consider removing it and running a malware scan and cleanup. We recommend the free version of MalwareBytes to help find and remove malicious programs on your computer. (

5. Sometimes third-party antivirus, security software, or firewalls can interfere with They can slow everything down, block certain items from displaying or opening in our program, or even cause the program to crash. Experiment by temporarily disabling these services to see if they might be the cause of your issues in TestOut courseware. If performance improves, consider whitelisting and, switching to a different program, or uninstalling that program and using your computer’s default antivirus and firewall software.

One program to note is Kaspersky. Kaspersky has a setting that is incompatible with our software. This setting injects its script into our script, causing hundreds of consecutive errors until the browser crashes or freezes.

Disable this setting: Kaspersky settings>Additional>Network>Traffic Processing: Inject script into web traffic to interact with web pages

6. Other Troubleshooting Ideas

  • If you are on a laptop, plug it in. Laptops may not focus on performance if they are set to conserve battery life.
  • Try using only one monitor. Your video adapter/card has to put every pixel on your screen as fast as it can. By having more monitors, it has to work harder and perhaps it can’t handle the load. Normally, you can have 3 monitors and everything works just fine, but this tip is for when things still aren’t working normally after trying everything else.
  • Along the same principles as the above tip, by reducing the size on the screen of the video you can reduce the strain on your computer and it might tip the balance into having the videos play smoothly. Try viewing the video outside of full screen and in a smaller window.
  • Try viewing the video at 1x speed. We let your browser play the video up to twice as fast as normal. If you notice stuttering and pausing like that, try slowing it down back to default speed to see if then your browser, network, or computer can better handle the load.
  • On a couple occasions, we have seen ISPs fail to efficiently route our content when IPv6 internet protocols were used. If you ping and it shows an IPv6 address, try switching off IPv6 protocols so that does not have to be translated to IPv6 from its default IPv4 by your ISP, then test LabSim again. If no difference is evident, re-enable IPv6. 
  • If performance only recently got worse, consider undoing recent changes that might have been made on the computer. This would, in theory, reverse an issue that resulted in performance loss. Uninstalling updates, uninstalling software applications (Programs and Features), and restoring your computer to an earlier point (Windows Recovery) are examples of undoing recent changes.


If none of this has helped, try using another computer/network, factory resetting or re-imaging your computer, or contacting TestOut Technical support. You can email us at, call us at 1-800-877-4889, or use the Live Chat function. We are open between 6:00am and 6:00pm Mountain time, Monday – Friday.