An Intel Arc GPU gets its full VRAM on a 2015 Xeon

Difficulty

Beginner

AI-buildability

5/5

It's a software-only boot hook installed on a Linux system you already have, so it's mostly running diagnostics and scripts, with no hardware work.

Time

An evening

Cost

$0

Estimates based on the original write-up. How AI-buildability is scored. Building with an AI assistant? Connect it to Afterware (free MCP server).

Intel's Arc cards are designed to map their whole video memory into the PC's address space through Resizable BAR. Boards without that BIOS option only expose a 256 MB window, so big allocations fail and data crawls through the gap. On a 2015 Supermicro X9DRH-7TF with two Xeon E5-2670 v2 chips and an Arc B580 12 GB, the 4K Vulkan filter test went from stalling at zero frames to 39–50 fps.

Rod Burlamaqui's arc-rebar runs from the initramfs on every boot, before the xe driver loads. It writes one PCI register and re-enumerates one PCIe root port, leaving the firmware, kernel and Intel's drivers alone. It ships with diagnostics that check the kernel log for the "Small BAR device" message and the "was not released" bridge signature, so you can tell whether you have the problem before you touch anything.

If you have an old Xeon or Core board gathering dust with an Arc card in it, this is the rare fix that costs nothing but a reboot. The project is free for personal use, requires Debian or Ubuntu, and the author says to back up first.