taken from the jackaudio.org site:
"JACK is system for handling real-time, low latency audio (and MIDI). It runs on GNU/Linux, Solaris, FreeBSD, OS X and Windows (and can be ported to other POSIX-conformant platforms). It can connect a number of different applications to an audio device, as well as allowing them to share audio between themselves. Its clients can run in their own processes (ie. as normal applications), or can they can run within the JACK server (ie. as a "plugin"). JACK also has support for distributing audio processing across a network, both fast & reliable LANs as well as slower, less reliable WANs.
JACK was designed from the ground up for professional audio work, and its design focuses on two key areas: synchronous execution of all clients, and low latency operation. More background information is available."
so jack is defiantly low latency, but i can't say if it will help processor power.
HP Pavilion DV9000 17" AMD 64 AthlonX2 with 4 Gigs of ram
Two MixMan D.M.² Digital Music Mixer
ION Discover D.J.
Behringer BCD3000 USB DJ Controller
Behringer FBC1010 Midi Foot Controller