My 2p on the impact of the new firmware on XE's.

Not so much a night and day change, but, I feel the overall presentation got more refined. More detail. This is particularly noticeable to me on bass definition and punch. Evident across mid's and treble too but I tend to hear bass first.

Where I think the XE set a new presentation which was a bit different to the typical M "house sound", I think this firmware is more like M house sound. Very, very easy to listen to with pleasure. Very satisfying.

I have been testing the direct inputs to the XE recently using a SB Touch optical and rPi USB connected direct to the master XE (bypassing the 818). [reason = too frustrated with the current issues with Roon dropping the ID41 as soon as the server start to choke with memory issues...see Roon forum for that FYI].

One thing that was immediately obvious to me was the improvement in SQ on those sources. The gap to ID41 performance closed with the new f/w. I speculate that this might be due to the changes in FIFO that are listed above.

I would still love to see M offer a new ID4x that was based on RAAT network coding (as per the latter M network devices). This would very likely bring the ID4x card up-to-date vs the 20+ year old Sooloos network protocol. They could align data rate capabilities whilst they were at it (i.e. 192k at least if not 384k to match the USB input of the XE).

Rgds,
Nick