Normally, the jogging feedrates are set in Motor Tuning when you indicate velocity. If it goes a lot slower than that, you might have a slow jog feedrate active. Hit the Tab key and see what it says under "Slow Jog". If it's less than 100%, you can change it with the slider. If you like having a slow jog rate sometimes, you can set it to a lower percentage, and hold down the shift key when you want to jog fast, which should make it revert to the master velocity.