Why does this happen? When I am downloading a game the CPU usage is at its maximum and the PC slows down. Other launchers do not give these problems when downloading games.

It's not just a gog problem... here it's happening with all clients...

i will test new drivers for my realtek lan, but i think that will be the same

I hope that it's only a client bug

This is only happening to me on GOG, on Steam, Origin and Battlenet the CPU usage increases, but it is normal. PC doesn't seem to be taking off, whereas here it is.

I have the same issue. The last two games I downloaded that were over 30 gig caused my system to slog and eventually freeze up. After the second to last issue, I needed to run start repair and after the last one, it took restarting three times before my pc would run. I only ever have issues when downloading with GoG's client.

sounds like you guys need to set a temp foler or perhaps just clear up some space

i figured out a little trick maby it will help ya :Lunch Gog -Account Settings - now check out Bandwidth - reduce the max consumption. Cheers;)