Zypper is ultra slow

I’m having huge trouble with zypper. The download just gets stuck for several minutes for each package (before the actual download starts).

I cant find any possible reason for this.

Maybe the mirrors are overloaded by the millions of 11.2 downloaders.
Might also be something in your network config.

Try YaST -> network settings -> disable ipv6

IPv6 is disabled, but it only seems to happen with small files. Big files seem to download just fine (actually a 100MB file was just downloaded in 3 seconds, afterwards a 80KB files was downloading 5 minutes).