yeah that is pretty good .
your 1 slow one may want 231.25 it may give you the same hash as the 237.5 gives you or it may even give you 460gh. it will also save power over your 237.5 setting.
What I found so far is :
batch 1 sucked
batch 4 was better
batch 6 was best
I am running these in my garage with temps about 92f in the garage.
Ok, so for a while I ran the 231.25 and was seeing ~450, that being said, I forgot the one pool the "bad" machine is on set up a new server with a hard diff of 512. So I switched to that, put the machine back to 237.5 and am now seeing ~480 where as on he old server I was getting diffs of like 1.48k and a hash of around 455Gh/s
So ya, that's interesting. I know some people argue diffs can't affect machines like that but I've basically just proven it does... at least with the S3's.
some pools have vardiff and don't care what you do.