What GPU Shared Memory Is and Why It Slows Your PC
GPU shared memory in BIOS is a setting that reserves a chunk of system RAM for integrated graphics, which can quietly reduce available memory and make a PC feel slower, especially when running modern, RAM-heavy operating systems and apps. Integrated GPUs have no dedicated VRAM, so they borrow from system RAM; BIOS options like DVMT Pre-Allocated or UMA Frame Buffer Size decide how much is reserved. The catch is that many systems keep this reservation even when a dedicated graphics card is installed and handling all display output. That means several gigabytes can be locked away from Windows and your programs for an iGPU you rarely use. According to MakeUseOf, one user with 16GB installed saw only 12.9GB accessible in Task Manager before disabling GPU shared memory, and the system felt “like 16GB again” afterward.
Check If GPU Shared Memory Is Eating Your RAM
Before changing any BIOS performance optimization settings, confirm that GPU shared memory is the problem. Open Task Manager, go to the Performance tab, and select Memory. Look at the top-right summary: the total installed RAM and the “Hardware reserved” value. If you see a large hardware-reserved chunk on a system with an integrated GPU, that portion is likely being used as the iGPU’s VRAM pool. This effect is most obvious on 8GB or 16GB systems, where losing a couple of gigabytes is noticeable in everyday multitasking. If you already have a dedicated graphics card installed and all displays are connected to it, that reservation gives little benefit. In that case, your goal is to free up system RAM by reducing or disabling the iGPU allocation in BIOS, while keeping the option to restore it later if you need the integrated graphics again.
How to Reduce GPU Shared Memory in BIOS
To free up system RAM without fully disabling the iGPU, reduce its allocated memory in BIOS. Restart your PC and press Delete or F2 during boot to enter the BIOS setup (your motherboard may show the required key). Switch to the Advanced view, then look for menus labeled Advanced, Chipset Configuration, or Graphics Configuration. In there, find an entry named DVMT Pre-Allocated, UMA Frame Buffer Size, or similar GPU shared memory BIOS option. Change this from its current value to the lowest available setting, which shrinks the chunk of RAM reserved for the iGPU’s frame buffer. Save and exit BIOS so the system restarts. Back in Windows, open Task Manager again and confirm that hardware-reserved memory has decreased. This approach is safer for most users, because the iGPU remains available as a backup display output if your discrete GPU fails.
Disable iGPU Allocation Completely When Using a Dedicated GPU
If you always use a dedicated GPU and want to squeeze out every megabyte, you can disable iGPU allocation entirely. Enter BIOS with Delete or F2, then go to Advanced, Chipset Configuration, or Graphics Configuration, depending on your board. Locate a setting called Primary GPU, Initial Display Output, or a direct Integrated Graphics toggle. Set Primary GPU to PCIe (or Discrete) so your motherboard prefers the add-in graphics card, and disable integrated graphics if a separate option exists. Save and exit. After this change, your PC will no longer display an image without the dedicated GPU installed and working, so only use it on systems where you are comfortable relying fully on the discrete card. For RAM-starved systems, especially 2x8GB setups, disabling iGPU allocation can free multiple gigabytes and noticeably improve responsiveness when juggling browsers, games, and background tasks.
Combine BIOS Tweaks for the Best Performance Gain
Disabling or shrinking GPU shared memory is one part of a broader BIOS performance optimization toolkit. Once you have reclaimed RAM, you can improve overall responsiveness further by enabling features such as XMP or EXPO for RAM, which let memory run at its advertised speed instead of the default base profile. MakeUseOf notes that DDR5 often defaults to around 4800 MT/s even if rated higher, and enabling the proper memory profile unlocks those tested speeds. Likewise, options like Resizable Bar or Smart Access Memory can improve GPU performance on compatible hardware by removing legacy VRAM access limits. The key is to document any BIOS change and modify one setting at a time, checking stability after each reboot. This careful approach helps you free up system RAM, speed up memory, and get closer to the hardware performance you paid for without buying new parts.