Linux 7.3 to include VRAM management improvements for better gaming performance

VRAM Management Improvements for Linux 7.3

Kernel patches focused on enhancing VRAM management for gaming workloads have been successfully merged upstream. These improvements are now slated for inclusion in the upcoming Linux 7.3 release, following a period of discussion and review on mailing lists.

Addressing VRAM Overcommitment

The primary goal of these changes is to improve system stability and performance when games or applications request more VRAM than physically available on the GPU. Historically, exceeding VRAM capacity often led to crashes and severe performance drops, making gaming unplayable. The new patches aim to make VRAM overcommitment primarily a performance issue rather than a stability one.

Performance Impact of Memory Eviction

When a GPU runs out of dedicated VRAM, some of the game's memory must be moved to slower CPU RAM. Accessing CPU RAM from the GPU is significantly slower due to the inherent speed difference between CPU RAM and VRAM, and the additional latency and bandwidth limitations imposed by the PCI bus. For instance, a PCIe 4.0x16 connection offers approximately 32GiB/s of bandwidth, meaning that if more than 1GiB of data needs to be fetched from evicted memory per frame, achieving 30 FPS becomes impossible.

Optimizing Memory Handling

The kernel patches work to minimize the negative impact of this memory eviction process. By optimizing how and when memory is moved between GPU and CPU, the system can better handle situations where VRAM is overcommitted, leading to a more stable and less severe performance degradation compared to previous behaviors.