Hi Guys,

I think Asus' SupremeFX 2015 onboard sound is very good, with sonic studio II you can adjust the sound with an EQ, Smart EQ, bass boost and supports 7.1. I'm just using the plantronics gamecom 380 stereo headset and it sounds great, bass in music is deep, rich and clear and the same with games, I can almost feel explosions at my feet. I'd say supremeFX is very comparable to alot of the quality sound cards.

wolfi3,
Seeing that you already have the dedicated sound card maybe you could do some comparison testing against the onboard sound solution and share your results with us here
I am sure there are many people that would be interested in your findings

Thanks for sharing

I am curious as well about how this z70's onboard sound compares. I'm still running my old xonar d2x which sounds fantastic and I know that its only a matter of time before it dies. The creative solutions have some very good specs thee days and onboard has never sounded that good to me when compared to a dedicated sound card.

The supreme FX only supports the front panel audio header for headphones. The ports on the rear of the machine are still fed by the same old Realtek onboard chip that's been there for years.*
If you already have the card it's a no brainer and depending on your use and speaker array you would probably get better quality using the Toslink out and an external DAC. All depends on the use and how picky you are on accurate reproduction, response, depth and punch. A million bucks on speakers doesn't negate the equation......crap in = crap out 100% of the time.*

I'd normally agree (almost automatically) that a sound card always outperforms motherboard embedded sound. It provides much more physical space for audio circuitry, lots of room for dedicated audio processing (and memory buffers), finer power regulation, large filter caps, chunks of metal RF shielding, and all the rest - instead of a chip plus a handful of tiny parts stuffed into a crowdy corner in the motherboard PCB next to all sorts of (more important) power and signal regulation hardware. It's like comparing a proper GPU card vs an embedded iGPU chip, where the lesser part is clearly intended to just provide basic functionality for minimum cost.

Specs for the ROG STRIX Z270G GAMING motherboard: "ROG SupremeFX" with "Crystal Sound 3". 8-channel HD audio built around a Realtek S1220A ("A unique audio codec designed in close collaboration with Realtek ... [it] features an unprecedented 120dB signal-to-noise ratio for the stereo line-out and a 113dB SNR for the line-in, providing pristine audio quality") along with power pre-regulator, audio shielding, separation of L/R PCB layers, audio (headphone) amp, de-pop, and quality capacitors.
https://www.bit-tech.net/hardware/2017/01/30/asus-rog-strix-z270g-gaming-review/6

Specs for the ROG Xonar Phoebus Solo soundcard.

In this instance the onboard sound looks so good (and/or the sound card looks not so good) that it's actually a tough call. A whole lot of emphasis and quite a few extra parts were added to the Z270G headphone output phase, so headphone audio quality should actually be quite superior, truly crisp and clean, even if the other audio output channels aren't quite as extraordinary. Hard to say without a take-apart, but it even looks like there's more headphone-dedicated circuitry on the motherboard than on the sound card. Then again, this Xonar can probably deliver better overall sound across more channels so it'll likely sound much better when used on any multi-channel or surround-sound speaker setup. And appears to offer more user configuration/selectivity/options in software, although you don't necessarily have to run the ASUS-provided software.

Actual sound quality might vary from game to game or from driver version to driver version. Maybe compare the two (listening on your usual headphone/headset or speaker array setup). Maybe try running audio benchmarks, although admittedly very few of us (even the "audiophiles" with trained ears) can easily discern a 0.00013% difference in distortion or a 1dB difference in maximal SNR, lol, especially when the digital audio source (music, game, etc) is not actually encoded in true "audiophile" quality.

Dedicated sound cards sometimes suffer from noise produced by physically or electrically adjacent hardware - things like GPU fans or HDD servo motors, line noise on power-carrying traces, "coil-whine" from oscillators, parasitics from all sorts of sources. This doesn't happen a whole lot, but when it does then the only "fix" which works usually involves physically moving or removing chunks of hardware in the chassis.