Universal Audio UAD1 Project Pak DSP Card (Macintosh and Windows)
DSP Cards for Computer Music work

Universal Audio UAD1 Project Pak DSP Card (Macintosh and Windows)
The UAD-1 Project Pak brings UA’s revolutionary combination of DSP hardware and highly-prized software plug-ins within the reach of small PC or Mac project studios with a limited budget. It is also how existing users can inexpensively take advantage of even greater power, by using multiple UAD-1 cards (up to four per system). The UAD-1 Project Pak supports 44.1 to 192 kHz sessions and is the easiest way to upgrade your mixes and get that professional polished sound using your existing DAW software/hardware without needing a computer upgrade.
Digital Signal Processor (DSP) Cards
DSP cards house purpose-designed micro-processors built specifically for digitally processing signals in real time, generally.
This is where you get to tap into the realm of true advanced audio processing power which utilise powerful fine-grained algorithms to give you superior effects and control.
More Details
If that's not enough then check out the following link for the full specifications - UAD1 Project Pak DSP Card