At the lower edge of the Z370 AORUS Gaming K3 we see the front panel headers, etc. and if we zoom in a tiny bit we'll see a bit more of the intricate details there.
The board is fitted with a LED strip header. Aorus Gaming series motherboards will support either 5v or 12v digital LED strips. RGB Fusion with digital LEDs comes with 9 new patterns and various speed settings with more to come.
So, the Aorus motherboards boast a LED system in combination with their RGB Fusion App, from the top of my head RGBW strips are now supported as well. To the left, the enhanced audio components like WIMA and Nichicon Fine Gold capacitors are used to provide power to the overall system. The board houses an ESS SABRE reference DAC and uses Realtek 1220 for the audio codec.
Once we look at them from a top overview, you can spot these metal PCIe strips (great for heavy graphics cards). And yeah, four PCIe x1 slots.