So I was using a very old GPU, it is Quadro FX 1800M. Feature level is 10_1, confirmed, couldn’t be wrong.
But UE 4.25 still says that it needs DX11 with feature level 10.0, which clearly the card supports.
What’s wrong then? Any place that I can actually check out the technical requirements for each version?
I seems to understand it now. Many thanks for the response.
As a side note, I just installed the lowest possible version (4.0) and it was able to start. I will see how it goes.
I’ll just add that the ability to run the engine below DX11 was deprecated around v4.16-4.17. Versions earlier than those could run with -OpenGL parameter, forcing DX10 mode (afair). Folks managed to run the engine on an Intel integrated HD3000 & 4GB of RAM back in the day (4-5 years ago?)
With no DX11 you lose 90% of the material pipeline, though - Shader Model 4.x. Not to mention overall stability. On the other hand, it’s probably a good enough experience to learn / study the engine a bit!
Over the years, it become more and more of a resource hog, especially the latest 4.26 is marred with performance inconsistencies.
When it comes to DX feature levels:
DX11 feature level 10_1
means level 10_1 feature of DX11 as opposed to level 10_1 feature of DX10. Think of it as a fallback mode for older hardware that does support DX11 but without of the new 11.x features.
There are devices out there that were released while we were transitioning from DX10 to DX11 and the newest features were not yet available; the manufactures moved on to produce new devices rather than update the old ones. Those cases are handled by the fallback features.