reBART UEFI driver brings Resizable BAR to Intel 8-series motherboards

A developer named roschank released reBART, an open-source UEFI driver that enables Resizable BAR on Intel 8-series motherboards. The driver works with Z87, H87, Q87, B85, Q85, and H81 boards. Reports say Intel CPUs since Haswell support Resizable BAR, but motherboard makers never released the necessary firmware updates for 8-series boards.

Image: TechPowerUp

The developer discovered that the 8-series software fails to map memory past four gigabytes, unlike the firmware in 7-series and 9-series boards. reBART allows the board to boot normally and shifts the GPU memory window above the 4 GB line just before the OS loads. Using the driver requires flashing a modified BIOS and applying a DSDT patch, though it does not need module patching.

Newer builds of the driver include experimental support for multi-GPU setups and Intel Arc cards. One user reported that an Arc A750 and an Arc B580 worked with an unlimited BAR size on a Gigabyte GA-Z87M-D3H running Ubuntu. However, one ASUS Z87-Plus owner reported that the board failed to boot after applying the DSDT patch. roschank has not shared any performance numbers.