Hello I updated my opera for 56.0.3031.0 on 31, Jul 2018
normaly I use 30+ tabs and use 3.0GB of memory.
now in this version I have a problem my committed memory usage it's going for 9.6GB with 15 tabs.
so I think its a bug in version 56.0.3031.0.
The version 56.0.3026.0 work normaly with 30+ tabs using only 3GB of memory .