[Troubleshooting] I have 16GB of RAM but Windows tells me to close programs when I am only using 10GB

###Troubleshooting Help:

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Describe your problem. List any error messages and symptoms. Be descriptive. When I play games that are RAM intensive I almost always get a low memory error and Windows tells me to close programs to prevent data loss. This is odd because I have 16GB of RAM and the warnings show up when I hit around 10GB. This is common especially when I am playing games like Cities: Skylines, running VMs and also using Chrome.

List anything you've done in attempt to diagnose or fix the problem.

I ran Windows Memory Diagnostic as well and memtest and there were no errors. My only idea left is that it is a software problem and I need to reinstall Windows. Thanks for reading and helping!