Please I need help for my sound system ??

I recently bought KEF 5.1 speakers, 2x Q500, 2x Q100, Q200 and Q400p

All connected to my Onkyo TX-NR809 receiver,

First of all, im totally Noop about speakers, i always use headphone with AMP/DAC, So please excuse my lack of info.

I just want the possible best sound from my speakers for GAMING only

My current setup is,

-dvi-hdmi cable from gtx580 to my hdtv
-dvi-hdmi cable from gtx550 ti to the onkyo (for sound only)

as i read the GTX550ti can bitsream audio to receiver, and can get Dolby true hd through it. but i only get PCM



even when i pley dolby D source, its the same PCM and not HDMI

the receiver setting is not touched.

Is worth to buy HDMI sound card to get dture hd for gaming ?
OR
I just use the PCM all ch stereo sound ?

Like i mention, I just want the most possible best sound from my speakers ?

This some screen shots may help



Thank you

Ok guys, i fixed it and now im able to get DTS-HD and Dolby True-HD, and sound is amazing, but why when i play DTS or TureUD , it is always show (DIRECT) in the AV receiver ?

I mean the sound info in the (TotalMedia Theatre 5) show DTS or True-HD, but in the receiver screen always show direct ?

Thank you