Am using a Virus Ti Desktop with a Mac running Logic on OS 10.7.4, Virus software 5.0.1.05. Was experiencing many pops and crackles but after changing the I/O buffer size from 128 to 256 the crackles seem to have gone away. Bit annoying though because 128 is a much better I/O for recording eDrums but there you go.
Hopefully this will get sorted very soon. It used to be PLAY software that caused these problems for me! 