To put this into some context, I have been using a cheap USB cable (from before and after the installation of the Gen 5 board), it's been consistant in my setup, there are no other devices between the iMac and the Yggdrasil. With further listening I'm quite surprised how well the DAC is sounding, a layer of grime seems to have been removed. I wasn't expecting such a significant improvement from the original Gen 3 board, frankly I thought all this USB interface talk was a load of hype but this has me re thinking the whole front end thing.