According to the manual you can control the speed in the BIOS, Hardware Monitor, SYS Fan1/ 2 Control. You can't check its speed because, unlike FAN1, there's no sensor for FAN2. You could buy a fan like
http://www.newegg.com/Product/Product.aspx?Item=N82E16835608004&cm_re=case_fan-_-35-608-004-_-Product and use an included inline resistor to slow it down or buy a fan controller like http://www.newegg.com/Product/Product.aspx?Item=9SIA4SR1R81448&cm_re=case_fan_controller-_-0SS-004J-000G4-_-Product.