Asus updated their list of X6 capable Motherboards. Not all have bioses listed, but I think they put it up there to show which ones they are working on. You will have to select CPU->Phenom->xxx X6

http://support.asus.com/cpusupport/c...Language=en-us

Code:
Crosshair II Formula	
Crosshair III Formula    	 	
Crosshair IV Formula    	0505 	
M2N68 PLUS    	1402 	
M3A32-MVP DELUXE    	 	
M3A78 Pro    	 	
M3A78-T    	 	
M3A79-T Deluxe    	 	
M3A-H/HDMI    	 	
M3N-HT DELUXE   3002 	
M4A77    	2004 	
M4A77D    2004 	
M4A77T    	2008 	
M4A77TD    	2007 	
M4A77TD PRO    	2005 	
M4A78 PLUS    	2004 	
M4A785D-M PRO    	0806 	
M4A785G HTPC    	1405 	
M4A785G HTPC/RC    1405 	
M4A785-M    	0906 	
M4A785TD-M EVO    	2006 	
M4A785TD-V EVO    	2005 	
M4A785T-M    	2006 	
M4A78-E    	2505 	
M4A78-E SE    	1505 	
M4A78-EM    	2007 	
M4A78-HTPC    		
M4A78L-M    	0705 	
M4A78LT-M    	0605 	
M4A78T-E    	3303 	
M4A79 Deluxe    	3402 	
M4A79T Deluxe    	3107 	
M4A79T Deluxe/U3S6    	3004 	
M4A87TD    	0704 	
M4A87TD EVO    	0605 	
M4A87TD/USB3    	0704 	
M4A88TD-M EVO/USB3    	1012 	
M4A88TD-M/USB3    	0302 	
M4A88TD-V EVO    	1015 	
M4A88TD-V EVO/USB3    	1015 	
M4A88T-M    	2003 	
M4A88T-M/USB3    	0304 	
M4A89GTD PRO    	1301 	
M4A89GTD PRO/USB3    	1301 	
M4A89TD PRO    	0702 	
M4A89TD PRO/USB3    	0207 	
M4N68T    	0706 	
M4N68T PRO    	0605 	
M4N68T-M    	0804 	
M4N68T-M LE   0704 	
M4N72-E    	2201 	
M4N75TD    	1001 	
M4N78 SE    	1306 	
M4N82 Deluxe    	2003 	
M4N98TD EVO    	0704