I'm wondering is it because your cpu has a better memory controller on the cpu since it is a "EE" or maybe you a have a "B3" board maybe or perhaps both.

Did also a PiRun with 228 bclk and higher Ram clocks.
Is this the limit on the board or just where you stopped?

Anyone can give me a hint what the new 1704 Bios does ?
All it does is give support for new cpu's for the board.

"[ 1704 ]
----------------------
Support new CPUs. Please refer to our website at:
http://support.asus.com/cpusupport/c...Language=en-us "