Originally Posted by geluadi2000
Ok.But let me understood :
-mainboard DH55TC and i5-661 is my configuration
-if mainboard and procesors ability to passthrough to HDMI(from motherboard) will be turned off when i will insert that HD5670 on PCIe
-how HD5670 will collect the sound and from where to passtrough my receiver to decode True HD and DTS-HD ?
No. Intel HD Graphics can be still available even if you insert a discrete graphics card (so you can use both GPUs under Windows 7/XP; Vista does not support such a configuration). Usually you just need to set the primary graphics to "IGP" in BIOS.
Every current GPU has its own HD audio controller, which collects audio streams via an appropriate bus (PCI Express bus in the case of a discrete graphics card) from the system memory.
Audio stream can be stereo PCM, DD, DTS, multichannel LPCM, TrueHD, or DTS-HD. The format depends on the settings of your player/audio decoder. For example, if you choose decoding TrueHD to LPCM in PowerDVD, PowerDVD sends decoded multichannel LPCM to the HD audio controller of GPU, then GPU interleaves audio in the HDMI signals and sends to AVR.