8500gt sonic ddr3 http://en.wikipedia.org/wiki/DDR3_SDRAM
128 bit, 600 MHz core clock, 1.2 GHz memory clock, 16 stream processor
8600gt 1GB ddr2 DDR2 SDRAM
128 bit, 540 MHz core clock, 800 MHz memory clock, 32 stream
i calculated the memory transfer rate and 8500gt sonic has 19.2...