it works fine, I have done it before, just bear in mind that usb is a lot slower than sata1 so loading times will be a bit slower, so it depends on the game. Normal games with loading screens will just have longer loading screens, mmos will likely be faster in some areas (usb ssd will still be faster than sata mech drive for random access) and much slower in others as data here tends to be loading dynamically depending on whats going on around your character.