I let mine set itself (row refresh) in Auto to 42, wich is the max for 903 and it is good enough. So is lower # here actually tighter or more relaxed?

UPDATE; Today I tested on 2nd mobo w/ 903 and the FSB strap only works if I choose 333 when on my 5:6 divider. I noticed no big difference in selecting 333 strap v/s auto since the only one that mine could use is 333. What do you guys noticing is setting fixed 333, if using a divider that only belongs to 333?