Transforms are super slow on external monitors
 

I'm running a MacBook Pro with 2 external 4K monitors connected through a DisplayLink-based dock. Things work beautifully as long as the monitors are in native resolution and in default orientation. However, as soon as I introduce any form of transformation (rotation or scaling) at all, the performance drops substantially. Visual updates are very slow, and if watching videos, the frame rate is markedly lower. I don't see this problem with Windows machines, so the problem seems to be specific to the MacOS drivers (I'm using version 5.2.4 of the MacOS drivers)

This leads to 2 questions:
1) Is this a known issue?
2) Is there an ETA for a fix?

Thanks!

Hey Dave, I experienced the same and agree the performance is a big problem for rotated displays even at 1080p. I couldn't imagine what you're experiencing at 4k with 4 times the pixels to draw.

I submitted a support ticket including all of the pertinent logging information months ago reporting this exact same issue. I unfortunately heard nothing back.

I see now DisplayLink has released "DisplayLink Manager" instead of their kext (kernel extension) and I gave it a shot today. It's a step in the right direction with native support instead of kexting but unfortunately rotation is not yet supported in "DisplayLink Manager". So we are still stuck on the "classic" drivers which have rotation functionality but the performance is a real problem as you mentioned.

I hope we hear from someone at DisplayLink about the timelines we can expect this problem to be resolved.