I managed to get to 738 with a M8E, but have no prayer for the 743 club.
It was the latest version of XTU as of last month. BIOS version was 1902.
Windows 8 works better than Windows 7 by 3-4 points.
XTU also likes lots of DRAM sticks -- fill up the slots. You're better than I am at tuning them, so I'll leave that to you.
Non-K's give up on AVX instructions when Bclk gets to 103 even with regular BIOS. The sweet spot seems to be as high under 103 as you can get -- 102.75 or 102.875?
One non-ASUS board I used could get to 102.9325, but it's 3rd and 4th DRAM slots were ****y. Score was better with the M8E.
Hope this helps
Jeff