I thought these were kind of cool. http://www.totalimpact.com/G3_MP.html Total Impact has begun shipping the mPower, a quad-G3 and quad-G4 PCI-based multiprocessing solution that runs Linux. The cards are compatible with both Power Macs and Intel PCs, and operate at speeds between 366 and 500 MHz. The 4x400 MHz G3 card with 128 MB RAM sells for $4,500 while the 4x400 MHz G4 configuration carries a $6,500 price tag. --