Intel Arc graphics cards heavily depend on Resizable BAR (ReBAR) for optimal performance, with Intel previously advising buyers without ReBAR support to choose other vendors. Developer Rod Burlamaqui has released arc-rebar, a Linux tool that enables ReBAR on Intel Arc GPUs for motherboards lacking native firmware support. Unlike previous workarounds like ReBarUEFI that require BIOS modifications, arc-rebar operates from the initramfs at boot without altering BIOS, kernel, or Intel drivers.
The tool addresses the PCIe switch limitation in Arc cards where the upstream BAR size restricts memory window expansion. Testing on a Supermicro X9DRH-7TF with dual Xeon E5-2670 v2 CPUs and 2015 BIOS showed dramatic improvements: B580 GPU VRAM window expanded from 256 MiB to 16 GiB, bandwidth increased from 15 GB/s to 392 GB/s, and a previously stalled 4K Vulkan blur achieved 39-50 FPS.
Limitations include requiring Above 4G Decoding and a dedicated root port, with only Battlemage GPUs tested so far. The tool currently supports Debian and Ubuntu, leaving Windows users without benefit, but it could make Arc GPUs viable for older server and workstation environments.
Source: TechPowerUp News · Summarized by HeadlinesBriefing