New Linux Utility Boosts GPU Bandwidth on Older Systems
The tool enables Resizable BAR support on legacy motherboards, allowing for significantly higher GPU memory access.
Updated on Oct. 25, 2026 in Computers
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Developer Rod Burlamaqui has released arc-rebar, a Linux utility that enables Resizable BAR support on legacy motherboards. The tool bypasses BIOS limitations to grant Intel Arc B580 GPUs full VRAM access.
Why it matters
This workaround allows users to extend the functional lifespan of older hardware for high-performance computing tasks. It demonstrates how software-level re-enumeration can circumvent firmware-level feature gating.
The utility successfully increased the CPU-to-GPU memory access window from 256MB to 16GB. This configuration change resulted in a bandwidth jump from 15 GB/s to 392 GB/s on an Intel Arc B580 12GB GPU.
The players
Rod Burlamaqui
A developer who created the arc-rebar Linux utility.
Intel
A semiconductor company that produces the Arc B580 GPU and C602 chipset.
The details
The arc-rebar utility operates by adjusting the GPU's Resizable BAR configuration and re-enumerating the PCIe root port during system boot. It requires Above 4G Decoding and sufficient memory-mapped I/O (MMIO) space—a method where the CPU reserves specific memory addresses for hardware devices—to function. Once initialized, the system reconfigures the GPU driver to recognize the expanded memory window, though the tool currently requires Linux kernel 6.12+ and has no Windows support.
Timeline
2015: The BIOS firmware era of the tested Supermicro X9DRH-7TF motherboard.
2022: The original launch of Intel Arc A-Series GPUs.
- 2026-10-25
Developer Rod Burlamaqui releases the arc-rebar utility.
The Tech Race
Modern GPU performance increasingly depends on Resizable BAR to allow the CPU direct access to the entire frame buffer. This utility breaks the hardware-generation barrier that typically forces users to upgrade motherboards to leverage modern GPU bandwidth.
Linux users running Intel Arc B580 GPUs on older motherboards can now manually enable full VRAM access without a BIOS update. The tool requires a system running Debian 13 or Ubuntu with Linux kernel 6.12+ to implement the automatic boot-time patch.
The takeaway
This utility demonstrates that performance bottlenecks on legacy systems are often software-gate issues rather than strictly physical limitations. Enthusiasts should monitor the project's repository for compatibility updates across different motherboard chipsets.
Further reading
Explore the latest developments in custom hardware integration on our Computers page.
Source note: This article includes information reported by TweakTown.
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