v11.1 uses "-dmem 1 -h 896" by default for Fiji chips,
v11.2 uses "-dmem 0 -h 1024".
First option works faster, but it requires more memory (2*896*2MB instead of 1*1024*2MB) and may fail or show very low hashrate in some cases. For example, in my tests it works fine for blockchain drivers but often fails in latest Adrenalin drivers, so I decided to reduce memory usage by default, for compatibility reasons. Of course you are free to try various settings and select the best for you.