We have developed a highly parallelized special-purpose computer, GRAP
E (GRAvity PipE)-3, for gravitational many-body simulations. Its peak
computing speed is equivalent to 15 Gflops. The GRAPE-3 system compris
es two identical boards connected to a host computer (workstation) thr
ough the VME bus. Each board has 24 custom LSI chips (GRAPE chips) whi
ch calculate gravitational forces in parallel. The calculation of the
gravitational forces is easily parallelized, since the forces on diffe
rent particles can be calculated independently. One GRAPE chip running
at a 10 MHz clock has a computing speed equivalent to 0.3 Gflops; the
GRAPE-3 system with 48 GRAPE chips thus achieves a peak speed of 15 G
flops. The sustained speed of the GRAPE-3 system reached 10 Gflops-equ
ivalent.