your 6805 score seems about right for a full gk104 chip with your 4670k. is your 4670k overclocked? 3dmark is reporting your 4670k at stock clocks, 3.4ghz with a 3.7ghz turbo. other tests with the 4670k report the same stock clocks but the users reported that the processor was actually overclocked higher but 3dmark was reporting the wrong clocks.
my 780+2500k scored exactly 3000 more than you at 9805. note my 780 is clocked at 1325mhz here so my score may seem a little high.
http://www.3dmark.com/3dm/2527133