Thanks for reply. I didn't think it would be an issue seeing as all the ps4 had to do is send out the 1s and0s and let the hdvd800 dac do the timing/ converting etc. the ps4 is just like a laptop with digital information stored on it, the hdvd800 should be dealing with the conversions etc. that's the point of an external dac, it's independent of the source.
Well, I am no expert on SOC design, hence I have no idea what can be achieved with the PS4's SOC format audio decoder.
However, I do believe an dedicated hardware decoder will work better here since they is less instructions to handle and less chance for interrupts to kick in. At least, for a dedicated hardware, you will have a on board buffer that stores the "1" and "0" that needed to be processed so that anything crazy happens inside your CPU will not have many effect on your single transmitting process.
As for most of SOC, they use system buffers which are shared by other applications. If some system level applications that has very high priority kicks in all the sudden, it might block the RAM access of your audio applications causing signal delays. If this delay is longer than your DAC's buffer, you will hear "problem" sound.
That is all wild guess from me. There is no proof whatsoever~
I just use it to justify the money I throw on my PC to get the gaming sound card. To have this dilution in mind, helped me sleep better:P