I've got two HDSP(e) AES32 cards in my DAW, and three of the AES loops are attached to Lexicon PCM units (one PCM81 and two PCM91's). I'm running Reaper.

Periodically, the Lex units act like they are delayed and the only way that I can get them back in sync with playback is to change the buffer size in the Hammerfall tray icon, and then back, which I realize resets the driver.

Once its working in sync it seems fine for playback, but as soon as I go to render something the PCM81 goes back to being delayed, I'd say the delay is about 120ms or so. Sometimes it happens with the PCM91's as well.

One card is the master clock (set to internal) and the rest of the AD-DA units are slaved and the clock returns to the second RME card.

Any ideas on trouble shooting?