Recently Intel & Microsoft acknowledged a memory leak when playing fullscreen games or using a fullscreen application using a different display resolution and/or refresh rate than your desktop's display resolution. As shown in the screenshot below, you can see that the 'pagefile usage' gradually increases untill you get a dialog saying "Low on memory", prompting to close your game / 3D application.
To know if you are affected you can use 'System Explorer', and monitor the swap file usage. A smaller page file is more likely to trigger the 'low on memory' message faster. Do not increase the page file to a very high capacity. It will not help.
In the screenshot below you can see that the bug was triggered while a affected game or 3D application was active in fullscreen with a different display resolution than the desktop was running at in Windows 8.1. Suddently the pagefile usage decreases, this happens when alt-tabbing out the game or 3D application.
These are the hardware requirements and operatings affected by the bug. You must meet one of the hardware configurations mentioned in #2.2 and the operating system(s) mentioned in #2.2.