Unofficial Resizable BAR support for Nvidia Turing graphics cards (requires modified UEFI)

According to Tomshardware, the developer “terminatorul” has released a UEFI driver that enables ReBAR (Resizable Base Address Register) on systems with Nvidia Turing graphics cards. Owners of GeForce GTX 16 and RTX 20 series GPUs can thus benefit from this function for the first time, which is normally only available for RTX 30 cards.

NvStrapsReBar: Modification of the UEFI firmware

The driver called “NvStrapsReBar” patches the UEFI firmware of the motherboard to adjust the BAR size. This can be done automatically or manually. However, it is important to note that there are risks associated with frequently overwriting the firmware.

Why no vBIOS update?

ReBAR is normally activated via a vBIOS update. However, this is not possible with Nvidia cards due to the digital signing and encryption of the vBIOS.

For advanced users only

Currently, NvStrapsReBar is only intended for advanced users and hobbyists. There is a small but real risk of damaging the motherboard.

ReBAR and Smart Access Memory (SAM)

AMD democratized ReBAR with the launch of its Zen 3 Ryzen 5000-series CPUs and RDNA 2 RX 6000-series GPUs in 2020 under the banner of Smart Access Memory (SAM). It’s a feature that has technically existed since PCIe Gen 2.0, but has been largely ignored by the PC industry.

After SAM was made public, along with some worthwhile performance enhancements, broader industry support for ReBAR began to emerge. Nvidia eventually offered a patch for the RTX 30 series to add support for ReBAR, and the RTX 40 series has had it since launch, but earlier GeForce series have been neglected. There are still some technical reasons why the NvStrapsReBar modification does not add support for GTX 10-series Pascal Nvidia graphics cards.

A performance increase is not guaranteed, because ReBAR does not allow a safe performance increase in every game/app. However, tests on Radeon GPUs show increases of between 5% and 24% in specific titles. However, there are also cases where it brings no benefits at all or can even degrade performance. This is why AMD and Nvidia have Resizable Bar profiles for each game. According to Intel, Intel’s Arc A GPUs should always have ReBAR enabled. The ability to enable ReBAR on Nvidia Turing cards is an interesting development for hobbyists and enthusiasts. However, it is important to consider the risks and limitations before installing the driver.

Source: Tomshardware