Resizable BAR
Definition
A PCIe capability for mapping a larger GPU-memory region to the CPU.
Detailed explanation
Resizable BAR is a PCIe capability that allows software to map a larger portion of GPU memory into the CPU address space than the traditional 256 MB window. Platform firmware, GPU firmware, hardware, and the graphics driver must cooperate. Its performance effect varies by workload and memory-access pattern. The capability changes the size of a PCI Base Address Register aperture; it does not add physical VRAM or bandwidth. Games and drivers can benefit when assets are transferred through larger mappings, but some access patterns show no gain or can regress, leading vendors to qualify behavior per application.
Where you are likely to see it
This term commonly appears while Windows is installing, recovering, or configuring a display adapter, monitor, or graphics application. The definition above gives the short meaning; the detailed explanation describes the term's role in the operating system and hardware stack.
The surrounding event and device model determine whether the term refers to Windows, an application, device software, or hardware. This glossary is informational and does not provide repair, installation, or technical-support services.
Related vocabulary
Explore connected concepts and nearby entries in the Windows hardware vocabulary.
- DCHDeclarative, Componentized, Hardware Support App, a modern Windows driver-package model.
- TDRTimeout Detection and Recovery, Windows graphics hang detection and reset behavior.
- RollbackSelection of an earlier retained software or firmware state.
- S.M.A.R.T.Self-Monitoring, Analysis and Reporting Technology for storage health data.