after I had long journey to pursuit the truth...
from this article http://www.techpowerup.com/forums/s.....d.php?t=180080

and this youttube video...


someone on Tom's Hardware forum also try to do that thing after hear people plea for confirmation about this...
http://www.tomshardware.co.uk/forum.....-graphics.html

and, YAYYY!!!! 8D third article that tested HD7750 is working for dual graphic option!!!!
so anyone who had AMD APU A10-5800K, update your catalyst to lastest version (13.4) and tell me again if you really want to test this thing out... and also I wondering if HD7790 or HD7770 is also work with dual graphics too... XD