Yep Skuzzy I found out 1 of them.
If you set up the Xonar to handle 192 Khz sample rate & start playing games the Xonar will creep out from time to time & lock up. Once I reset the sample rate back down to 96 KHz for games--no more problems.
As I read up on this I found that most games are written for maximum sound sample rates of 96 Khz (Creative sets the standard since they're the leader in this area as I understand it & all Creative cards max out at 96 Khz) so it seems that the driver may have been freaking out trying to sample game sound at a rate that games are not written to be run at, IMHO. But you're the expert in this area so does this make sense?
It also could be heat related as there are no heatsinks on the DSP's & since the Xonar uses auxillary 12v power to do it's thing you know it's gotta run somewhat warmer than the other cards out there & on my Abit IP35 Pro mobo the PCI-E 1x slot is above the PCI-E 16x slot that has my GeForce 7900 GTX vid card in it & below the NB P35 chipset w/ passive heatpipe fin cooler--it's probably a safe bet that I ain't got a good enough flow of air around it to keep it cooled sufficiently when pushing the card to it's max capacity. But this is just subjective commentary as I don't have any creditable proof.
The 192 Khz sample rate is geared more toward music reproduction as I understand & when I played my music CD's at this setting I saw no problems or issues w/ the Xonar at all.
Hopefully Asus will tune the Xonar drivers to automatically adjust the sample rate to fit the usage in the future so this issue doesn't occur. But IMHO this ain't even a show stopper.
If you get 1 of these suckers, just remember that the DX is 6 3/4" long & might not fit on some mobos due to placement of adjacent equipment around the PCI-E 1x slots. Mine cleared the 1st DIMM slot on my mobo by 3/16". If you get more ambitious & get the D2X it's 7 1/8" long (I got that 1 also-it's as large as a Radeon 9800 vid card!) & it wouldn't clear the 1st DIMM slot. You have been warned!

Pair the Xonar up w/ a quality set of speakers.....................
..........& see for yourself.
