Key information
Developer Rod Burlamaqui has introduced arc-rebar, a Linux utility designed to activate Resizable BAR for Intel Arc graphics cards on motherboards lacking native support. This tool operates during the initramfs phase at boot, bypassing the need to modify system firmware, kernels, or official Intel drivers.
The software functions by interacting with the PCIe switch integrated into Arc hardware to enlarge the GPU memory window. By writing to the ReBAR register and rescanning the root port, the tool addresses limitations where small upstream BARs previously restricted performance.
Testing on a Supermicro X9DRH-7TF system with a 2015 BIOS demonstrated significant improvements, with the CPU-visible VRAM window expanding from 256 MiB to 16 GiB. VRAM bandwidth increased from 15 GB/s to 392 GB/s, allowing a 4K Vulkan blur task to achieve 39 to 50 FPS.
While currently tested on Battlemage hardware, the developer anticipates similar functionality for Alchemist cards. Users must still ensure Above 4G Decoding is enabled and the GPU occupies its own root port. The tool is compatible with Debian and Ubuntu, offering a potential performance boost for older workstations.
