I haven't tried it myself, but this thread:
8KHI2304 bios is discussing it. It's mainly for performance when coming out of the S1-S3 state (suspend states). There is still some things to work out, but the general concensus on the thread is that the 2221 bios is the best at this time. There's more detail on the thread that I won't get into, but it looks promising once it's done.