Unless I turn off ground plane on render mode, zooming in and out on my perspective view or moving objects will be sluggish. same happens on artic mode. and it also happens, even with ground plane off, when I zoom in close to object to grab onto the wire frame. This all used to not happen on my 1440p screen
Same issue with both a rx470 and a gtx 1650 on latest rhino with latests drivers and antialising off
Ground plane is extremely slow on my PC (also at 4K, but using Nvidia GTX 1660 Ti), so I always keep it off…
I don’t know if there’s anything that could be done to improve those particular features on low-end GPUs, maybe, but…that’s what you’ve got there, they’re not really adequate for 4K use. You’ve got over twice as many pixels to push vs 1440p, and more of your VRAM is consumed. I don’t imagine the performance impact is a smooth linear thing, it’s more like it’s fine until it hits some sort of wall that makes it much worse.
While GTX 1660 Ti 6GB it not a high-end video card by today’s standards, I would not call it a low-end either. By the time of its release (year 2019) it was a middle class video card whose performance was nearly identical to the middle glass GTX 1070. Rhino 7 was released in 2020. My video card can handle 2,5 GB large 3dm files with plenty of geometry in the viewport, so that’s not he case. I design cars for a living and my files consist literally every single component, including bolts and cables, as well as several versions of some parts hidden in layers.
Ground plane works slower even with a simple single box in the 3d scene, which means that the problem is not caused by the video card itself.
It may be related to the 3d mouse driver, though. When I turn on the FPS counter of Nvidia through the GeForce Experience panel, the former shows relatively same framerate no matter if I use Ground plane or not. However, rotating the viewport via the 3d mouse feels considerably slower with Ground plane on and just one simple box in the scene, despite that the reported average framerate stays same (min and max framerate between 23 and 51 fps, average is 48 fps). Turning off the Ground plane results into 32-60 fps, average is 55 fps (or about 7 fps more compared to when the Ground plane is on). I doubt that my GTX 1660 Ti is so slow that even a single NURBS box can’t be rendered at a stable 60 fps and sometimes drops to 32 fps; the issue must be in the program itself. For some reason, the Ground plane adds some lag (delay) to the camera rotation, probably about 300 ms or so. There is no lag with Ground plane turned off.
I have a 1080ti that stomps all over that, and I’m not moving to 4K until I upgrade it. People have different definitions of “handles.”
It all depends on personal preference. Car design and engineering requires very high screen resolution and a big screen size to see all the tiny details together. I work on a 42,5" 4K Sony TV whose IPS panel has great viewing angles and offers pretty natural picture (nearly perfect factory calibration), which easily beats the majority of PC monitors. This is just the right size and screen resolution for doing my daily job. 
Well I was just wondering if there was something like rendinging the perspective mode at a lower resolution, or Doing something like FSR.