I posted about this, on various forums, Steinberg, RME and here .....

Had to find out myself that my windows 10 64bit system which ran fine for about a year, all of a sudden developed this occasional stuttering and pulsating audio behavior.

The Fix was first removing all my AMD Radeon graphics drivers and in stalling a basic one windows 10 chose itself, probably older one.

Done all sorts of sometimes expensive experiments first (f.i. bought an USB PCIe Freslogic card with four onboard controllers and a new SSD because someone mentioned 5 years old one could be the cause). With 'standard MS' drivers: no problems any more, but then Microsuck, THEY REALLY DESERVE THIS HONORABLE TITTLE BY NOW, I AM ANGRY, decided to 'update' some driver, and i had to get the latest AMD drivers to fix the occasional lockup hanging of Windows 10, this mostly on closing a program or folder. Spent an awful lot of time first, like removing and reinstalling VC+++, SFC and harddisk checks, running loose spyware and antivirus programs, removing hardware drivers, registry checks, listening to 'experts' blaming certain plugins and jBridge even.

Wavelab 9.5 has graphics issues from DirectX 12, so i still run it in Windows 7 compatibility mode, so that it chooses an older DiriectX; maybe a thing you could try fist.

Both AMD an NVDIA seemed to have put out new drivers about a week ago for this Microsuck originated (MS thank you) bug. TW fall creators i steer and still stay away from, and windows update is (again) switched off in my services.

And now the occasional stutters are back LoL. BTW Going back to Windows XP might cause problems with recent software and drivers, unless you decide to stick with older stuff, as a friend of mine does. Might be that Windows 7 is a better choice today. Or 8.1 ??

I am testing now with a device manager disabled AMD HD audio device chip on my graphics card, doubt if that helps. (One should also disable any audio chip on your mainboards' BIOS IMO).

PS, you mention buffersizes, i WAS able to run USB audio (RME UFX) with 94 samples (before WAS was? LoL), now i don't dare to go below 256 .... counting all the time i spent on fixing windows problems from even Windows 98 on they ow me a healthy pension addon bonus. -F