Why can/does sound quality change over same USB?

Hello. I have often been frustrated with USB connected DACs connected to either Apple Mac Mini or various Windows builds; sometimes when the USB dac is connected, music sounds washed out and poor, and other times exactly perfect and beautiful.
Sometimes I have found that simply changing to another USB port on the PC will “fix” this. What is going on that can have such a sonic effect? SHould I just get a USB “de-crapifier” and all my problems will vanish?

I have noticed this with:
AudioQuest Dragon Fly Black/Red
Schitt Bifrost USB Gen 2
PS Audio Codex
Marantz SA 8005 with USB input;
I always stream lossless from either Tidal or Qobuz. I have also noticed this with network attached sources.

Is it an OS clock/timing prioritization thing? Is it a network bandwidth issue? I figured that, since all the above devices ARE operating in Asynch mode such problems are non relevant. WRONG!
It really is crazy. Sometimes when the USB enumerates the sonic result is washed out, flat, no contrast. There is no dropout or obvious distortion, just at really low-fi sound like i’m listening to much lower bit rate streams.

I’m sure there is a technical reason. Please shed insight! I really want to embrace and be friends with PC based audio. I notice this most on my work setup where i plug direct into PC with DAC and listen to headphones. My home setup is Roon Core --> Network --> Sonare microRendu --> Meitner DAC


I noted the same as you and ended up with boxes and PSU’s all over to try and achieve some consistency. My latest purchase is a networked DAC. I also have a setup which bypasses USB in favour of i2S over HDMI. Both are very good and are one two box setups respectively.