I had my doubts about v9.1 performance few pages back. In the end it were stats of ethermine that got me confused
ethermine pool had some problems yesterday, a lot of people noticed it.
Is this the sha256 checksums for your Window ETH miners?
EthDcrMiner64.exe (ETH 9.1)
1e3dce0e3dd3b7ca7e96d731ccc2cfc778dcaa5d9e550676820ff710ebe9fdd8
EthDcrMiner64.exe (ETH 9.0)
ce3734f66a90eeebb3d4a37f267cb6fa879c769cdc00768f1979e3da9535f239