By Sebastian Castellanos
Publication Date: 2025-12-19 19:21:00
Resizable BAR (Base Address Register) (or ReBAR for short) is a modern PCI Express feature that lets your CPU access the full video memory (VRAM) of your GPU directly, removing the old 256 MB limitation and potentially reducing bottlenecks in data transfer between the CPU and GPU in games. When supported by your hardware (CPU, motherboard, and GPU) and properly enabled, ReBAR can improve performance in certain titles, making gameplay feel more responsive and consistent.
Each of the three major GPU vendors supports this feature, but the implementations differ. AMD introduced it first as Smart Access Memory (SAM) with their RX 6000 Series GPUs, and its Adrenalin graphics driver interface has an on/off global toggle for it on compatible hardware when BIOS support is present. NVIDIA added ReBAR support starting with its RTX 30 Series GPUs with a post-release VBIOS update, but their drivers only enable it for specific games that they’ve validated. Intel’s Arc GPUs not only support ReBAR but actually require it to achieve their full performance. Across all three GPU vendors, the underlying mechanism uses the same standardized PCIe feature, but the implementation varies by GPU architectures and drivers.
Since NVIDIA is the only GPU vendor that enables/disables ReBAR on a per-game basis, it is possible to use advanced third-party tools like NVIDIA Profile Inspector to force ReBAR for officially unsupported games, potentially improving their…