It took some testing and installations to find out that the cable is to move with other guitar software packages for co-operation. Have with me Guitar Rig 5 running on the PC, the guitar over the Real Tune cable to the USB port. GR 5 emulates a plurality of amplifiers, distortion pedals and other tools; this plethora of sounds would otherwise only with many cases more expensive to achieve hardware.
The key is the ASIO4ALL -Treber currently freely available on the Web in the version 2.11 Beta2. (For 2 channels separately) specify in Guitar Rig -Setup then Rocksmith cable as input.
It will save you in this way an additional USB audio interface, for domestic use, it is always enough. Latencies are with me ok (Notebook Intel 2Kern 2.5 GHz, 4GB)
Should run on OSX, not yet had time to test.
Have Fun!