I have a list of about 1200 games across several platforms, so that probably has an impact here, but I find the performance of the GOG Galaxy 2.0 client quite poor when scrolling through my list or waiting for UI updates in general (search also feels sluggish). The framerate is low and it doesn't feel as responsive as other similar lists (e.g., Steam's list view).

I managed to spike GOG Galaxy 2.0's CPU usage at 23%(!) on a 3930k just by scrolling my library up and down. Attached is a screenshot showing 20% usage while all I'm doing is scrolling.

I can't push Steam above 6% or so by scrolling in the same fashion (quickly up and down over a short section of the list), and on top of that it feels much quicker while doing so. I can push Steam up to about 12% by switching my mousewheel to free spin and just letting it ride, but if I do that with GOG it gives up even trying to display the content of the list and replaces everything with blank placeholder lines until I stop scrolling.

I like the new client, but I will probably end up not using it simply because of how much less fluid it feels.

edit: Do image attachments not work? It doesn't seem to let me put an imgur url in here either.

edit2: Just unlinked Steam to see if reducing the size of the library made a difference, still very choppy scrolling with ~200 games.

You mention the free-spin mode. I have a Logitech MX Master mouse and exactly the same problem with the performance of the Galaxy. Maybe it has something to do with it?

For me, the worst performance is noticeable in the grid view when additional data from Atlas updates such as Title, Rating, Status, etc. are enabled.

I noticed that it gets worse the longer Galaxy is running.
When the Chrome browser is running in the background, it also affects the performance of the Galaxy.