Sorry about the 'non-official' response, as this is an MSI Retail Product 'user' forum. An 'official' MSI tech will make an appearance & post once in awhile, but not very often. Anyway, PCI_E2, E4, & E6 can be populated with three GTX 470's, but there would be no other slot open for anything else other than the dedicated E1 slot for the sound card.