What GPU Shared Memory Is and Why It Shrinks Your RAM
GPU shared memory in BIOS is a configuration that reserves a slice of your system RAM for the integrated graphics processor, which can leave less usable memory for Windows, games, and everyday applications even when a discrete GPU is your primary display device. On modern systems, the iGPU does not have its own dedicated VRAM, so it borrows from your main memory through this reserved pool, often called DVMT Pre-Allocated or UMA Frame Buffer. That reservation can turn a 16GB system into something that feels closer to 12 or 13GB under load, increasing paging, stutter, and app slowdowns. According to MakeUseOf, one user with 16GB installed saw only 12.9GB accessible in Task Manager before disabling GPU shared memory, which explains why gaming and multitasking felt tighter than expected.
Check How Much RAM Windows Can Use
Before you change BIOS settings, confirm that GPU shared memory is the problem. Open Task Manager with Ctrl+Shift+Esc, then go to the Performance tab and select Memory. Look at the Total and Available values; if you installed 16GB but see a noticeably lower total, a chunk is being reserved. In the same panel, note the “Hardware reserved” value, which hints at how much RAM is blocked off for devices like the iGPU. If hardware reserved memory is sitting at a few gigabytes on a desktop with a dedicated graphics card, you are likely losing RAM to GPU shared memory. This quick check helps you justify the effort and gives you a before-and-after baseline once you change the GPU shared memory BIOS setting to free up system RAM.
Enter BIOS and Find the GPU Shared Memory Setting
To change GPU shared memory BIOS options, restart your PC and press Delete or F2 during the splash screen, as most motherboard vendors use those keys to enter firmware. Once inside, switch to Advanced mode if needed so you can see chipset or graphics options. Look for sections named Advanced, Chipset Configuration, or Graphics Configuration; naming varies, but they usually sit under the same umbrella as other PCIe and display settings. In that menu, scan for entries like DVMT Pre-Allocated or UMA Frame Buffer Size, which control how much RAM is reserved for the iGPU’s frame buffer. If you do not see them immediately, use the BIOS search feature some newer boards provide, typing “DVMT” or “UMA” to jump straight to the shared memory setting.
Reduce or Disable iGPU Memory Allocation
Once you have located DVMT Pre-Allocated or UMA Frame Buffer Size, change the value to the lowest option to disable iGPU memory allocation as far as your board allows. This frees RAM for Windows and games while still keeping integrated graphics available as a fallback. For an even bigger BIOS performance optimization, you can disable the iGPU entirely on systems that always use a discrete card: in the same Graphics Configuration menu, set Primary GPU to PCIe or switch integrated graphics to Disabled. MakeUseOf notes that your PC will not display anything without the discrete GPU after this change, so only do it if your dedicated card is reliable. Save and exit BIOS, then re-open Task Manager to confirm your total and hardware reserved memory now match your installed RAM more closely.
When Disabling GPU Shared Memory Makes the Biggest Difference
Freeing GPU shared memory in BIOS makes the most impact on systems with 8–16GB of RAM that juggle gaming, browsers, and background tasks. Games that stream large assets, creators using heavy browsers and chat apps, and anyone running Windows 11’s growing background processes can feel the benefit when the full memory pool is available. Combined with other BIOS performance tweaks, like enabling XMP or EXPO profiles so RAM runs at its advertised speed, your PC can feel noticeably smoother without any hardware change. As MakeUseOf points out, many owners never look at their firmware, so they live with underused components. Spending a few minutes in BIOS to disable iGPU memory allocation is a one-time change that helps your system use the RAM you paid for every time it boots.