I was looking for that too as a couple of the high end Rampage and Crosshair boards that just came out have them wired to a similar connector glued to and buried under the armor, though it looks a little bigger.
See my above post it could be their but the striped down picture of the board also left that off.It's the only thing i can think of that makes sense.
And the manual for this model also fails to mention where the battery is. Although it does mention removing the battery if CLR_CMOS button fails to do its work. So it looks like those Asus boards indeed have battery under heatsink - which also means OP board is probably defective.Another model of a ASUS board the battery is on the back of the USB port and 2 pin wire.
Unless maybe he leaves it unplugged so much the battery died? I mean still it shouldn't die that fast, and in the end even if it DID die it should still boot up and not require a hard CMOS reset via the rear button to boot.And the manual for this model also fails to mention where the battery is. Although it does mention removing the battery if CLR_CMOS button fails to do its work. So it looks like those Asus boards indeed have battery under heatsink - which also means OP board is probably defective.
Yeah think they removed it for the pic of the bare board.See my above post it could be their but the striped down picture of the board also left that off.