Nouveau-DKMS is in development as an out-of-tree spin-off of the open-source NVIDIA "Nouveau" driver focused on providing better support for NVIDIA GeForce 400/500 "Fermi" series graphics processors and potentially other generations too pre-Turing where the modern Nova driver is in development by NVIDIA.
For those using the aging ~16 year old Fermi graphics processors on Nouveau today with the upstream Linux kernel have a pretty poor experience due to re-clocking challenges and the open-source developers largely focusing on much newer generations of NVIDIA GPUs. Nouveau is principally focused on GTX 1600 / RTX 20 Turing GPUs and newer where there is the GPU System Processor (GSP) to enable easier driver support and similarly the in-development Nova Rust driver is only focused on Turing and newer too. The official NVIDIA Linux driver has long treated Fermi in a "legacy" driver branch that also puts those still using these decade and a half old GPUs in a poor spot.
The Nouveau-DKMS out-of-tree driver is working to improve Fermi support with full Core, Shader, Voltage, PCIe Gen1/Gen2, and bidirectional DDR3 Memory Reclocking. Plus this driver is working on supporting a variety of other newer features not supported by the upstream Nouveau driver.
Those curious about this Nouveau-DKMS out-of-tree activity can find the Fermi-focused improvements happening via this GitHub repository. There are also adjoining user-space utilities too for managing the dynamic re-clocking.
While Fermi is the main focus right now, there is a project roadmap where they also outline hopes for improving support for newer Kepler, Maxwell, and Pascal graphics cards too for getting up to the pre-Turing support.
It's too bad it's all happening downstream though but we'll see in time if any of this kernel driver work manages to make it into the mainline Nouveau driver. This work appears motivated in part for aligning with AliveOS development as a new minimalist Arch-based Linux distribution expected to debut in early 2027 with a custom Cinnamon desktop, XLibre display server, Btrfs snapshots, and other modern desktop features.