Doing some further work with my system, I found that “useplatformclock yes” is not so great actually, but the other two do help. In the end, I found that my motherboard is very finicky about the video card installed. Both an Nvidia NVS 510 card and an AMD FirePro W4300 caused audio clicks and drop-outs, Returning to my old Radeon 4850HD cleared up any audio problems I was having. I haven’t had a drop-out since. I hope this card can continue to hang in there a while until I can find a modern video card that works well with my system. Maybe I should keep it simple and just get a Radeon 7750 with multiple DisplayPort outputs. I remember Matrox was really great for staying out of the way of the rest of your system, but their latest cards have ridiculous pricing given the feature set.