Why is DX11 so slow?

Just converted DX9 patch to DX11 and the framerate drops significantly. Tried windowed renderer, fullscreen and render target. All becomes approx. 50% slower than the original DX9 patch. On different PC’s with fast GPU/CPUs.

Any hints how to use DX11 and still achieve the framerates over 30fps (or even up to 60)? Are there any specific settings or renderer that are faster than others? I couldn’t find much documentation on DX11 render nodes, so any tips are very welcome.

I’d guess you forgot to change texture format in Renderer (DX11 TempTarget) nodes, since it is defaulted to a slowest one (R32G32B32A32_Float) - try R8G8B8A8_UNorm or smth

Other than that, no idea what could be wrong, without seeing the patch…

It’s quite likely that default format creates problem indeed (specially 32 floats target really hurts on laptops).

As a side note I narrowed it a bit and did a bug report here:

So I can set default properly in next dx11 release.

Thanks for your help!

Changing RGBA32 brings a bit more speed, but it seems there is something else still blocking. The patch is rather complex. I was trying to simplify it for an upload if you want to have a look, unc. But as more I simplify it, as better the performance gets…

It seems the problem lies rather in the extensive use of certain functions. E.g. using VLC with spreads over 100 images/videos in several subpatches. I did that before in DX9 and the performance was ok, but random crashes occurred when using multiple instances of VLC. In DX11, VLC runs stable, but it also affects the overall performance more significantly.

Still trying to optimize things and identify causes.
Thanks again.

If you use vlc for image, it’s pretty likely you’ll have a decent slowdown (in dx11 definitely, pretty sure in dx9 it’s not ideal either).

interesting the “R8G8B8A8_UNorm” thing!
There are other random tip for DX11 performance?

+1 luper
open a new thread

+1… no text …

Thank you vux! Your VLC tip was incredible helpful.
Btw, any solution for using bold text in DX11? Found this: , but it seems that it works only in 2D.