I have both the Renderer and Quad USB in my Diamond V. In the beginning there was Quad USB, Windows OS, and it was very, very good. Then came the Renderer. It was more lifelike, more real. The Quad USB more detailed, less organic. Then I decided to put out the switch between the Renderer and my DIY music server. Linux was the way to go. My Ubuntu Server became a DLNA server also and connected to the Renderer directly. Fantastic achievement. In this stage, forget the Quad USB. BTW forget Windows for audio. I've tried them all. WinServer 2012R2, single and Dual PC, Win 10, with Process Lasso, Fidelizer, AO, JPlay, JPlay Streamer, JCat USB card and JCat battery power, endeless PSU types including batterys, you name it.
The next step was trying Audiophile Linux OS. Amazing. Cantata player and Quad USB were back on top. Next I tried WTFPlay. The best ever. We are literally at scene/event. That's where I am now. No JCat Femto USB card or similar. Nothing. Total DAC USB cable straight from the mobo.
All this to say that everything matters and the result is system dependent. Maybe I will achieve to put the Renderer again on top. One thing for sure: you Renderer owners only will know what is it capable of if direct connected to the PC.
Better than this? Maybe the MSB UMT Transport to be able to use I2S connection. I own and tried once Pink Faun bridge card with North Star Supremo DAC, via I2S. Very interesting. Very raw sound.