Way back in 2014 when Microsoft was still finalizing DirectX 12, Nvidia pledged that all of its then-current hardware would support the new API. At the time, that meant GPUs from the Maxwell, Kepler, and Fermi families. Kepler and Maxwell DX12 support came around on day one of Windows 10's release, but Fermi languished on DirectX 11, meaning it never completely supported the OS's WDDM 2.2 standard. That is, until now: the latest 384.76 drivers quietly added DirectX 12 support for Fermi GPUs.
The new feature wasn't listed in the patch notes, possibly because users have been complaining for a while about Nvidia's apparent failure to live up to its promise. The change was first spotted by a couple of sharp-eyed folks on the Guru3D forums. User "maur0" noted that the DirectX diagnostic tool was now reporting Direct3D version 12 on his GeForce GTX 570. Then "user1" promptly ran the extremely-intensive 3DMark Time Spy DX12 test on his GTX 560M and achieved a staggering 373 points.
For comparison's sake, a GeForce GTX 660 or GTX 750 Ti can put up around 1200 points in the same test. Overclocked Maxwell parts and high-end Pascal processors like the GeForce GTX 1080 can breach six thousand. The GTX 560M is a mobile part based on GF116—a six-year-old GPU at this point—and frankly, the fact that it can complete the benchmark at all is impressive. Hats off to Nvidia for continuing to support truly ancient hardware.
The poor performance in Time Spy is likely attributable (at least to some degree) to the fact that almost none of the DirectX 12 API features are supported by the old Fermi hardware. Some folks coaxed user1 into running the DX12 Feature Checker on his laptop's GPU, and the resulting list is an excellent exercise in the many ways of reading the word "no." Still, even if the performance isn't great, DX12 support for these old cards means that they can stay in service for years to come. Also, simpler DX12 titles that aren't as demanding as benchmarks won't simply bomb out on otherwise-capable cards, like Vulkan apps forever will.