Personally I think it would be the better option than 4x 680's... most notably - "air to breathe".
I can't explain the high score... obviously the primary graphics are the 590. The GTX 560 I would assume is for physX. It's safe to ignore the Intel HD graphics because his board features Lucid Virtu so 3DMARK sysinfo is going to list it. My 2500K machine, Z68 and 6950, 3Dmark lists the HD 3000 as secondary~ http://3dmark.com/3dm11/3417734 ... Still and comparing~ http://3dmark.com/compare/3dm11/2707969/3dm11/3422587 ... doesn't make sense.
Obviously 6990x2 scaling is horrendous at low resolutions (highest 60%), actually pathetic. Ignoring this, he's running single channel and how in the hell does he nearly double my score in the combined test?