There a several 7mm cartridges. If you mean the 7mm Remington Magnum (or just "magnum") The magnum is about 300fps faster than the 7mm-08. This means flatter trajectory and more recoil.

If deer is on the menu go 7mm-08 its plent of punch for a deer, is still considered a "flat" shooter, isn't rough on recoil and is accurate.