Yeah the UD3H was the first board that arrived. I ended up reviewing four boards (with limited CPU availability) and my test run is 40+ hours each (a working week) plus writing on top of that, so I had a hard time trying to test them all one-by-one in reasonable time. Of course I kept getting BIOSes from some companies the day before my review went up! That's how it is with a launch, and I didn't get around to retesting the first one on the latest BIOS because it was a case of test, next, test, next.
I have said I'll see if the latest BIOS is better and update the image, though F6k seemed to have issues with setting memory timings on my kit so I'll retest with F5.
But in general, I'm not sure whether it's just platform maturity, but the Z87 range is tending to have a DPC Latency of 150-200, whereas Ivy was going below 75 with the right board. Of course for a DAW you're going to strip everything out, I test mroe on a 'default' system setup and OS with the manufacturer's software installed.