This topic is a bit misleading as the SSE3 emulator for SSE2 CPUs is simply broken. I have tried this an many other legacy kernels with no success. On SSE2 CPUs, when you boot into SL with this or other kernels you will see that your background is pinkish, icons look over saturated, time will be negative, date will be all screwy and many many other instabilities.

Would be nice if someone would correct the title of this topic to Legacy SSE3 kernel instead of misleading people into thinking Snow Leopard will work on their SSE2 CPU.