What Is SupremeFX IV?
SupremeFX has been a staple addition to Republic of Gamers motherboards ever since the very first Crosshair. Its design is focused on improving sound quality beyond the standard that most motherboards include, with a focus on gaming. The SupremeFX brand signifies not only a single audio component like the audio codec, but a complete set specifically curated to work together. As such, SupremeFX III and IV have pushed the SNR almost to the limit of what can be done with onboard audio.
The Red-Line – Continuing The Trend Of Audio Isolation
First introduced with the SupremeFX III, the IV continues the red-line physical isolation of the PCB between the analogue audio signals and the digital ones across the rest of the board. This reduces any potential interference as there is no chance for them to interact. To highlight this split, the PCB line is see-through, allowing the red lighting produced by a row of LEDs on the back of the PCB then shine through, giving it a subtle glow from the front. By still incorporating the audio codec onto the main PCB itself, this frees up an extra slot (if anyone remembers the original SupremeFX) or rear I/O space, where it would otherwise reside. 
Headphone Amp
While some of the Xonar range and new ThunderFX have headphone amps built in, no motherboard has integrated one before now. Using a high fidelity Texas Instruments TPA6120A2 amplifier the 'front stereo' (green) 3.5mm output can amplify up to 300 ohm. [gallery include="" size="large" link="file" template="file-gallery" columns="2"]
ELNA Capacitors
Apart from the 1500uF capacitor, the rest of the Maximus V Formula uses 15k hour metallic black capacitors. These are ideal for the extreme applications that ROG motherboards require in the digital realm, but they are not the best fit for analogue audio. The ROG audio team sourced specialty ELNA capacitors, which are specifically designed for audio applications thanks to characteristics like super-low ESR, and they put them exclusively inside the SupremeFX IV red-line area. [gallery include="" size="large" link="file" template="file-gallery" columns="2"]
1500uF 'Buffer' Capacitor
Despite the red-line separation, there still needs to be power (and signal) input. The 1500uF capacitor is made to straddle the two sides, smoothing out any power fluctuations on the digital side while providing ample power reserve for sudden demands on the analogue side. When used with line powered speakers or headphones (i.e. those that have no additional socket/battery power for the speakers) the sudden power draw can cause audio clipping, which the large capacitor aims to prevent.
EMI aluminum cap
The aluminum cap has evolved from SupremeFX III, from a basic all-over cover to the new backlit logo. While the technical aspect of the covering - to entirely isolate the codec inside - remains the same, the red backlight aims to sync with the red-line in properly showcasing this feature. Why is an aluminum cap required? The inside of your PC case is subject to many different high-frequency interferences, which can constructively or destructively affect the audio output. Modern hardware has progressively reduced its effect by lowering voltages, improving construction and with better PCB layout has placed the audio processor at the furthest corner. However, the effect will be negated if you sit a powerful graphics card and fan right on top of it, which can happen in a multi-GPU environment. The EMI shield creates a barrier to this, further benefiting SNR. The EMI cap is in red, the 1500uF cap is in blue: [gallery include="" size="large" link="file" template="file-gallery" columns="2"] SupremeFX IV is currently available on the Maximus V Formula.
