Comment by necovek

Please describe "failure": I've had a Sony Vaio Z with switchable Intel/Nvidia graphics in 2009 before Optimus (though that did require some tinkering), but had GTX 960 and GTX 970 (actually still do) in a couple of computers, along with an integrated Intel and AMD GPUs in a bunch of laptops.

Note that kernel is totally unconcerned with DPI in general: it only cares about physical pixels and reports physical dimensions to apps — if scaling caused kernel level issues, it might be related to proprietary driver issue (they frequently lag in Nvidia's case).

I never used ultrawides myself, but if the monitor did not report proper "timings" and available resolutions, you might have needed some manual tweaks.