If you get an audio interface with more efficient ASIO drivers than ASIO4ALL, yes, you can run more stuff at once. But just for clarification:
The reason you buy one is to get inputs and outputs, not for better processing. If you want better processing, the best way to get monster results is to upgrade your processor or RAM (or both). Getting a better soundcard will make a noticeable difference (esp. if it has on board DSP), but not as much as upgrading your processor (or RAM if that's a bottleneck for samples).