Latency issue with Lexicon Lambda and CWMC4

you're probably still trying to run it on WDM driver mode and ASIO will probably work better

OPTIONS>AUDIO>ADVANCED>DRIVER MODE = ASIO
click OK
MC4 will need to be restarted.

then you might need to adjust the latency buffers.

OPTIONS>AUDIO>ADVANCED>ASIO (button near the bottom)

that should bring up the lexicon's software.  find the hardware buffers in there and decrease them.  and see if that works.  usually 256 is the highest you want to go for low latency monitoring.  if you go too low, tho, you'll get popping, stuttering and clicking and even dropout.