I am experiencing a 1 second delay from my audio interface which is an M-Audio Oxygen 49 and the GPO 4.0. I am new to this so I'm not sure if there is something that just needs tweaking in order to have the keyboard interface at real-time. I am currently just using my HP laptops speaker and soundcard. I do have Pro Tools 8.0 LE so I'm not sure if I set it up through that driver if this issue would rectify itself or not.
Use your dedicated ASIO drivers (tools>preferences>audio API and device in Aria Player), and adjust Buffer settings (buffer size a bit lower down) to reduce latency. You may not have ASIO drivers for an HP onboard soundcard, so connect an external one, or try out asio-4-all as an alternatived driver for your onboard one.