This has been a project that has facinated us for a long time, Realtime audio processing via a computer.
In the past, the latency (time delay) to process the signal was too large, resulting in music artists being unable to perform with the delay due to the way we perceive sound.
A fantastic white-paper is available that talks about The Effects of Latency on Live Sound Monitoring
In the video below, resident propeller-head Adrian Davis tests out a low latency setup to find the delay and CPU usage on a Apple Mac Mini Server (i7 2.3Ghz Quad Core, 8GB Ram, SSD) with an Allen & Heath iLive iDR32, Yamaha Dante Accelerator PCIe, Akitio Thunderbolt Chassis and Waves Multirack, to try and find the best configuration of this setup for Latency vs. CPU
to iLive Dante
The results marked in Bold yeilded the best results in this test configuration at the time of testing, your results may vary.