What GPU Shared Memory Is and Why It Eats Your RAM
GPU shared memory in BIOS is a setting that reserves part of your system RAM as video memory for integrated graphics, which reduces usable RAM for Windows and games, and can make a 16GB or 8GB system feel slower and more crowded than it should under everyday workloads. On CPUs with an integrated GPU, there is no dedicated VRAM, so the iGPU borrows system memory instead. The problem appears when you have a discrete graphics card installed: many boards still reserve a fixed chunk of RAM for the iGPU even though the discrete GPU handles all display output. According to MakeUseOf, one user saw Task Manager report only 12.9GB usable out of a 16GB kit because of this reservation. Disabling or shrinking that pool can free between 32MB and 2GB of RAM, which matters a lot on modest gaming builds.
Check How Much RAM Your GPU Is Reserving
Before changing any BIOS memory optimization settings, confirm that GPU shared memory is the culprit. Start by opening Task Manager (Ctrl + Shift + Esc), then go to the Performance tab and select Memory. Note the “Hardware reserved” figure and how much RAM is listed as usable compared to what you installed. If you see a significant gap, that portion is blocked off for hardware, including the iGPU. Systems with discrete GPUs can still reserve hundreds of megabytes or more for integrated graphics, which is wasted for gaming when the iGPU is disabled in practice. This is where disabling shared memory for gaming can provide a quick win, especially on 16GB or 8GB setups where every megabyte counts. Once you know your baseline, you will be able to see exactly how much RAM you reclaim after BIOS tweaks.
Find the GPU Shared Memory Controls in BIOS
To free up system RAM, you need to enter the firmware and locate GPU shared memory BIOS settings. Restart your PC and press Delete or F2 repeatedly during boot to open BIOS; most consumer boards use one of these keys. Look for an Advanced section, then a submenu like Chipset Configuration or Graphics Configuration. Motherboard makers use different labels, but you are searching for options such as DVMT Pre-Allocated or UMA Frame Buffer Size, which control how much RAM is reserved for the iGPU. You may also see a Primary GPU or Primary Display option that chooses between PCIe and integrated graphics. Take a moment to read on-screen descriptions and avoid touching unrelated settings. If your BIOS lets you save profiles, store a default profile first so you can roll back easily if anything behaves unexpectedly later.
Reduce or Disable Shared Memory to Free Up RAM
Once you have found the iGPU memory setting, you can either shrink or disable the reserved pool. For a cautious BIOS memory optimization, open DVMT Pre-Allocated or UMA Frame Buffer Size and switch it to the lowest available value, often 32MB. This restores most of the reserved RAM while still allowing you to boot on integrated graphics if your discrete GPU fails. For dedicated gaming rigs, you can disable the iGPU outright: set Primary GPU to PCIe, or turn off any explicit integrated graphics option. MakeUseOf notes that disabling the iGPU freed about 1GB of RAM, with typical gains ranging from 32MB to 2GB depending on configuration. Remember that with the iGPU disabled, your system will not display anything without the discrete card installed, so only choose this if you are comfortable relying on that GPU.
What to Expect After Disabling GPU Shared Memory
After saving your changes and rebooting, return to Task Manager’s Memory view to see how much RAM you managed to free up. Budget gaming builds with 8GB or 16GB benefit the most, because those extra hundreds of megabytes reduce swapping and stuttering in games and heavy apps. Windows 11, with its growing background processes and AI features, can feel smoother when more physical memory is available for foreground tasks. Keep in mind that discrete GPUs still maintain a shared memory pool managed by their driver, and some hardware-reserved memory also goes to USB devices, memory-mapped I/O, and drivers; that portion cannot be reclaimed. To push performance further, you can combine this change with other tweaks like debloating unnecessary services or using tools such as Microsoft’s RAMMap to clear cached memory during long gaming sessions.