interface latency

I travel full time (most of the time) and don't have an amp. I use my macbook pro (mid 2015 model/ 2.2 GHz Intel Core i7/ 16 GB 1600 MHz DDR3) with Garageband and Guitar rig 5 for amp/effect emulation. As an interface I use an old M-Audio Mobile Pre (version one) which is probably 10 years old...