Color correction 4k

Hi,

I have a 1080p sequence in which there is 4k video clips. I use proxies which work fine until I get into the CC part.

When I start color correcting the 4k clips, whether or not proxies are on, it gets very laggy, the only work around I found is to nest the clips, thus becoming 1080p dimension, and thus PP not lagging anymore.

Having nests in the timeline is pretty annoying because it becomes much harder to edit in case I want to cut back again a clip after CC.

My question is : is there a way to color correct 4k clips without lag and without having to nest them ? (apart from buying a new computer of course).