They are all B2 Steppings - but I found that under phase the CPU is FSB restricted, but on a DFI mobo you can overcome this by setting the DRAM speed higher - most of my scores were achieved using a 225Mhz FSB but running ram with a multiplier that ran the ram at 275mhz - also you can use a higher LDT multiplier (x5 up to 225mhz).