At the time of writing and using the processors I had at hand, the 0505 was the best solution (we tested non 45nm) not to mention that 45nm is not fully available yet. I am currently testing the 0702, which may be included in a follow up if deemed necessary. Later BIOS releases can always change the way the board sets up the straps and how they interact with various CPU's. The main issue with Transaction booster in the Maximus Formula is working out the PF level offsets between BIOS's, that's all the difference usually is, together with a couple of the secondary timing ranges.
Transaction Booster is a function we have urged Asus to return to logical user level control (among other improvements that should be available in this price range), rather than the offset levels (with amalgamated TRD phase register shifts) that are not really intuitive. The X48 board already features these improvements and we hope they filter down to the lower models.
regards
Raja