Update:
Tides of Vengeance brings new optimizations for medium-high setups, allowing the WoW game engine to better use multithreaded processors. These changes show improvements of around 20% to framerates, depending on system specs.On top of these changes, players using Nvidia cards should see even more improvements, as their most recent driver update (December 3rd) includes further optimizations, adding another 5% or so improvement to frame rate values.
It is important to note that all these optimizations are available only for users using DirectX 12 (Windows) or Metal (macOS) graphic APIs

https://www.wowhead.com/news=289041/...s-of-vengeance