OK, in which case you need to find out whether that is causing the problem.
Are there enhancements for that which can be disabled using a dedicated tab in the same way as I decribed below? e.g. on an IDT HDA tab within the speakers playback properties?
If so try what I suggested below. Something is writing to audiodg.exe and not releasing the memory so it will be related to your sound drivers
somehow and you need to find out what's causing it so you can stop it.
On mine, you can literally see the memory use start growing all the way up to over 1.5GB as soon as you enable the enhancements. Disable them and the growth stops. With them disabled on my machine the memory use for that file never grows much above 10 MB after a fresh start, which is as it should be.