I have read both, and the jealous, angry, mercurial, vengeful God of the Old Testament most certainly has the same traits as the Muslim God.
So you didn’t read the Bible (nor the Koran), then; just admit it. Instead, you read the propaganda of others. Nothing mercurial about the God of the Old Testament whatsoever, who gave Israel and Judah multiple warnings and multiple chances to stop their idolatry and child sacrifices.
There is also another chief difference between the God of the Bible and Allah: the former specifically claims the title “Father” whereas the latter is adamant about not having any children.