The G ISA has proved its retargetability by being implemented on three disparate hardware platforms. The first implementation was on a platform with software address translation and floating point; later versions incorporated these features in hardware. The SPS-1 and SPS-2 have distributed memory and use message passing. The PPWB (a Sun 3 workstation with simulated parallelism) uses memory buffers and files to store task memory images. Future implementations could use shared memory, or a combination of shared memory and message passing. Performance on the SPS-2 was dominated by software address translation. However, on the SPS-2 and the PPWB, program performance has approached that of a native implementation. Comparing C and Fortran programs compiled using Myrias software and Sun software shows a low cost increase for G, with beta-release compilers. There is every reason to expect that the delivered translator will match or exceed the performance of existing commercial compilers. >