Intel chipsets have more usable bandwidth available. The other chipsets tend to have errors which cause the audio data (and all other data flowing over the PC except AGP Video) to need to be resent. This causes the processor to have to send the data again, and if it does this too many times in a row, the data doesn't get there in time, and there is a dropout. Intel chipsets have always been more capable of insuring that the data gets there correctly and quickly.