I have the same platform, but different motherboard manufacturer.
Wel it seems you understand it, but there is no way to play fluently any HD content without DXVA.
Using XMBC, the option is System\\Video\\Playback\\Allow Hardware Acceleration (DXVA2)
Using MPC-HC: Options / Internal filters and check that "H264/AVC (DXVA)" is selected.
Then Options / Playback / Output, select " EVR Custom Pres" to enable DXVA 1 and 2.
You don't need any external codec or codec pack to enbale DXVA with MPC-HC or XBMC.
My AMD E-350 is usually sitting around 20%-30% CPU usage when playing 1080p H.264 videos, and it's of course totally fluid (this not the best decoding quality, and the video post-procesing/rendering is very very limited, but it's working fine with a correct quality and very low power usage/noise)