in short yes they are differet. The GTO has 512 mb memory while the GT has 256. Its hard saying which would peform better but my money would be on the GTO. It has a the same stats and design as a GTX only a lower memory speed and 100 less dollars. The GTO has a memory clock of 1320Mhz while the GT's is 1500, GT's clock speed 500mhz GTO-650mhz, while they cost around the same i bet the GTO would outperform the GT this must have been a new release becasue its the first i'm heard of this model. Anways thats the difference