The Cray-1 had 160 MFLOPS, and a single Pico has about 133 KFLOPS, so 8 of them would be just over 1 megaflop (not accounting for any overhead). So about 1/160th!
That's only part of the story. Cray spent a lot of time architecting an I/O system that could keep the CPU fed. So peak and sustained performance were closer than a lot of systems.
