A1 A2 lose sync

[iwl]

Hi, I have a USB-Speaker on A1 WDM and a HDMI TV with Box on A2 WDM, Win10.
They are out of sync from start 75ms with 512 Buffer Size and 150ms with 1536 Buffer Size.
And they loose sync more and more in quite short time, Loading Setup again fixes it, but it drifts again.
I thought 1536 Buffer may improve this, but not, only increases the initial sync gap as above.
Any Idea how I can improve this, already started trying other than wdm driver, but couldn't improve it.
The USB A1 seems to have a Minimum Buffer of 1056 as WDM BTW.

Thank You iwl

[iwl]

HDMI TV A1 WDM, USB Box A2 WDM, WDM Buf 2048 seems to fix it.
No initial Sync GAP anymore and no drift yet...