The 6500 is below our requirements and is not recommended as a processor that will allow you to take full advantage of a Motu Audio Core system. In addition, several users have reported problems with the 6500 series when ever using any Audio Card along with a MIDI interface. Our investigations have found that when ever using any PCI Audio Card at the same time that there is any sort of serial activity, you would encounter intermittent freezing on a 6500 series computer. These symptoms have been reproduced with several popular Audio/MIDI programs and Audio PCI cards. This hardware anomaly with the 6500 is something that a processor upgrade would not address.