MB toslink out vs Soundcard coax out: Which provides best sound?

Probably a stupid question. My old soundcard [M-Audio Delta 2496] still works with Win7, but all I use it for is to send spdif coax signal to my Benchmark DAC. Motherboard [Asus M5A97 Evo] has integrated sound with toslink out. Is the quality of the output signal identical via either MB or soundcard to Benchmark DAC?

Does using the soundcard coax out bypass all card circuitry or does the card provide essential conversion that may be superior to what the MB does? The answer may be obvious . . . or not . Help appreciated.

As both are digital I don't know if there is really any difference. Try them both and see which one works better.

I have a recording studio and I still see people using the old M-Audio stuff so it must still work OK. But, newer on-board sound cards have advanced over the years and are on a par with separate sound cards. Although I have a Roland Octa-Capture for my recording, I use the built in Realtek on my sound card for PC sound. I used to use separate "audiophile" PC sound cards but no longer.

Thanks for the reply, Fireberd. I'm afraid I was a bit unclear, however, in the original post [which has been edited]. My question isn't coax vs toslink but rather motherboard digital out [Asus/AMD/Realtek?] vs. soundcard digital out.

I understand that the "value" of a soundcard is its DA converters. But in my case, as I'm not asking either the PC or the soundcard to do any DA conversion, are the results identical when I use digital out? My guess is that it doesn't matter, but that's just a guess.

There can be differences in digital quality, but in most cases it can't be heard.

I don't know if the "digital out" on the M-Audio is straight digital to digital or if the M-Audio first converts the digital to analog internally and then converts it to digital for the output. This could make a small difference in the digital signal quality, but probably not a real concern. In the PC digital out, the same process happens. But again probably not a concern.

The biggest concern in the link would be the digital to analog conversion in the DAC.

No, I don't know if the data is "raw" digital data or if it is first processed in some way. However, I suspect there is some type of processing.