I'll go against what most comments said and recommend DirectX 11. Yes, DXVK will translate it to Vulkan anyway, but Larian's own Vulkan implementation is definitely less stable compared to DX11.

I've experienced multiple crashes during simple things like opening the character sheets using the tab key, or crafting alchemy potions. I never had a single crash using DX11. I used Fedora 39/40 and openSUSE Tumbleweed, so the kernels were fairly recent. Radeon 7800 XT GPU.

I had the same experience under Windows 10 (before I switched to Linux), Vulkan has smoother frametimes but DX11 is more stable.

YMMV, this is just my experience from almost 400 hours played so far.

DirectX is a Windows thing, so you'll just have those calls translated to Vulkan under the hood (DXVK). You'll probably get better performance from just setting it to Vulkan directly.

Edit: As some others say, for BG3 specifically, DXVK does a really good job. My personal experience is that "the best" option is very patch dependent. At launch Vulkan was best, then after a few patches did DXVK ran better, but personally I'm back to straight Vulkan, for no other reason than wanting to be a +1 in the statistics.

You find out by installing MangoHud and checking which works better.

Shortly after release neither one made any real difference for me.

Depends on the games and their implementation of Vulkan but generally Vulkan is preferable and typically runs much faster.

Dxvk is usually better, but using vulkan is the better strategic move, you'll increase their vulkan stats and provide QA. Good native vulkan support will beat dxvk every time.

as far as im aware its always better to use vulcan

Always is better to use vulkan!

Up until a few months ago, Vulkan was very unstable on BG3. It’s been fine for a while though. I haven’t made performance or smoothness comparisons though, I just default to Vulkan and it’s been fine.

Try them both and use the one that works better

Vulkan

Directx 11 in this case, played bg3 on Linux and that was the only option that worked, and it did work quite well.

As for when to use one or the other, just check protondb. People usually leave what they played on, they even leave some useful launch commands or solutions to issues that could possibly arise, so it's always worth a look.

Vulkan, always, just to echo the other comments. This game runs pretty well too, at least in my experience. MP even works!

Usually depends of the game, no idea in BG but I would recommend testing both

Vulkan in proton was busted at launch (couldn't start the game), but I've heard it's better now. If you have issues then you can always switch.

I'm still running windows for now, but even then Vulkan has de-fucked a few games for me. Given the option, always Vulkan.