As a fellow Pyramix (Native) via Boot Camp with RME interface user, I have some experience with running Windows on Mac laptops. One of the main sources of DPC Interruptions is the Battery monitor. Disabling the driver for this in the Windows Device Manager cleans those up, but you should take care should you ever be using your computer without AC, as you'll receive no warning that your battery is getting low.

Other sources of interference can come from certain Anti-virus programs. I've found that Windows Defender which comes with Win10 provides good protection with relatively little processor interference. Certain other AV products can be quite problematic, and a search of the Pyramix Forum - http://forum.merging.com/ - will help identifying these (cough, cough, Avast, cough, AVG, cough, hack, sputter).

Get yourself a free copy of the latest version of LatencyMon - https://resplendence.com/latencymon, and run the test for ten minutes or more. The program will identify the programs, processes or services which are contributing to the highest levels of processor load (DPC interruptions, ISRs, etc.). Disable or stop the processes that this test reveals, then repeat to see if you're still experiencing the interruptions. You may need to do this a few times to identify all the culprits.

Unless you're doing live punch-ins and overdubs, you should run your UFX+ at its highest processing latency (1024 samples for SRs of 48k and below, 2048 samples for higher rates). This will allow your processor time to get to all the tasks it needs to perform in time, and has the benefit of allowing your machine to run cooler. In addition, I'd recommend installing MacsFanControl - https://crystalidea.com/macs-fan-control/download, which is a small footprinted program which allows you to change your machine's Fan behaviour so that it starts to ramp up fan speed more gradually, starting at a lower temperature. In addition, I use a hardware laptop cooler with my MacBook Pro, as I like to baby my machine.

Also, please note that Win10 2004 has its issues, and Pyramix is technically not supported on Win10 versions later than 1909. This is especially important if you are running Pyrsmix MassCore. Merging even provides a file that allows you to specify the "Target" version of Win10 you want on your machine (hint: it's 1909 if you're using Pyramix 12), found in the Merging Knowledge Base article about configuring Win10.

Are you saying that you own Pyramix MassCore, and that disabling MassCore provides some relief? Not a great solution, I'm sure you'll agree, since you paid for MassCore, and it seems a shame not to use it. If I've misunderstood what you wrote, and you do not have the MassCore option, then disabling multi-core support (however you did that) for Pyramix Native should have no effect at all, as Native is single-core only. The scuttlebutt is that the upcoming Pyramix 13 Native version will be provide multi-thread, muti-core support.

A very good source for taming the excesses of Win10 can be found on the AskWoody.com website, where you'll find suggestions about how to regain control of your computer's updating processes, and information regarding problematic monthly updates. The Merging Knowledge Base is an excellent resource, particularly those articles dealing with configuring the various versions of Windows, as you've already discovered, and could be a useful guide even for those who are not Pyramix users.

As I am not currently running Win10 on a laptop, I may have given you incorrect information regarding the Battery Monitor - it was available in Win7, but it's possible that it's no longer there in Win10 - sorry about that.

As far as other power settings, have you done what you can to follow the instructions found here?
https://confluence.merging.com/pages/vi … werOptions

That text suggests that because you're running a laptop, you won't be able to set up and use the "Ultimate Performance" power plan, but setting maximum and minimum values to 99% should be fine - the main thing is that you do not want throttling of the processor power, as the switching between power states can generate some large DPC interruptions. Basically you want it running at full capacity all the time, living with the attendant power consumption and heat issues involved.

Keep in mind that the latest information in Merging's Knowledge Base is for Win10 version 1809, so running a more recent version, such as 1909, it's likely you'll encounter some discrepancies between what they recommend, and what you can do with your machine. As a last resort, you could contact support@merging.com to see if they can suggest anything, but because 1909 isn't supported yet, you may not be able to get a satisfactory answer. On the other hand, maybe they just haven't gotten around to updating the Knowledge Base - after all, there's only about 20-30 people working at Merging altogether, and I'm sure they're all beavering away diligently on Pyramix 13.

No, no user BIOS on Boot Camped Macs. Holding down the F7 key while starting up Windows won't do anything. The Boot Camp software sets up an EFI partitioning scheme to allow you to boot from multiple partitions on a single disk, which acts like somewhat like BIOS, except it's not really user accessible - at least I've never been brave enough to attempt it. You might want to run the Apple Software Update on your Windows installation to see if there is a more recent version of Boot Camp available for your machine. I'm running 6.0 on my 2012 Mini, but I know there is a 6.1 version. It's possible that the drivers that make up the bulk of the Boot Camp update/upgrade might give you more streamlined performance, and therefore fewer audio interruptions, should a Boot Camp update be available for your machine.

In any event, LatencyMon is going to show you where the most egregious sources of interruptions on your system are coming from, and I'd get the most recent version and see what it finds. After all, power management and anti-virus were just guesses on my part - your interruptions could be coming from something which I've never encountered.