It's not uncommon for certain games to perform better on Nvidia or AMD hardware. Maybe there was an official sponsorship by one company or the other -- Nvidia, "the way it's meant to be played," and similar -- or perhaps there was some collaboration during development. In most cases those partnerships end up meaning the eventual game performs a little better on that brand of hardware, but it seems not always. In the case of Battlefield 5, it's the exact opposite.
The first alpha for the upcoming World War II shooter has been available for a few days now and early testers like PCGamesN have been having a go at it. In their testing, however, they found that the supposedly built-to-work-best on Nvidia game, was actually a better performer on AMD hardware.
At both 1080P and 1440P resolutions, Battlefield 5 had far better frame rates on an RX 580 than it did on a, supposedly comparable, GTX 1060. In DirectX11 testing, the GTX 1060 managed 45 frames per second on average, while the RX 580 pushed out nearly 70. DirectX12 didn't improve things for the Nvidia card either, as it actually dropped its average to 41 FPS. In comparison, the RX 580 stayed the same, while improving its minimum frame rate to 59 from 56.
1440P is just as pronounced, with the GTX 1060 in DirectX 11 and 12 respectively managing just 34 and 32 FPS, while the RX 580 was able to achieve 49 and 47 FPS in turn.
It's not like Nvidia cards struggled across the range, with more powerful cards like the 1080 and 1080Ti absolutely smashing it and delivering fantastic frame rates. But perhaps not as much as they should.
It's still early days in the game's testing, but it will be interesting to see if things improve for Nvidia as time goes on, or if AMD will maintain its quite obvious performance lead.