Old Testament is Most Violent
A look into the verbatim text suggests that the content in the Quran is not more violent than its Judeo-Christian counterparts. In fact, of the three texts, the content in the Old Testament appears to be the most violent.
Killing and destruction are referenced slightly more often in the New Testament than in the Quran (2.8% vs. 2.1%), but the Old Testament clearly leads—more than twice that of the Quran—in mentions of destruction and killing (5.3%).