That's just numbers. They might well show that there are some significant stat differences but in a blind test most people wouldn't be able to tell the difference between 60fps and 70fps and most people wouldn't be able to tell if certain visual effects are turned off like AA. Yes, the FPS and effects might go up, but in real world visual terms there's not a massive difference.
There was an article on here a while ago which someone posted where the author had let a load of gamers play a game on two machines (this was a year or two ago I think). One cost about £1500 and had a high end PC with a 7970 with everything on max. The other was some low end budget PC (about £500) with a load of settings lowered. Most gamers couldn't tell which PC was which by playing the game.
Booting in half the time using an SSD provides a noticeable significant difference.
But it all depends on personal preference of where your priorities lie taking into account value and diminishing returns. IMO on a 1080p 60Hz screen, the improvement going from one 780 to two 780s has such limited visual improvement that there is no value to it. Lot's of cost for very minimal actual visual improvement. If someone offered you four of Girls Aloud for the night for £500 then said you could have all five for an extra £3000... yes there's a slight improvement, but it's not worth it.
If you're moving up into the 120 or 144Hz screens or 1440p resolution then the actual visual improvement increases and thus makes it more value for money to get the 2nd 780. But I doubt most people would look at a game running at 60Hz on a 1080p screen on mostly max settings with no AA and think, "this looks rubbish, I need another 780".
But I know you like your SLI 780s so we'll leave it at that
EDIT... plus this build isn't just for gaming...
There was an article on here a while ago which someone posted where the author had let a load of gamers play a game on two machines (this was a year or two ago I think). One cost about £1500 and had a high end PC with a 7970 with everything on max. The other was some low end budget PC (about £500) with a load of settings lowered. Most gamers couldn't tell which PC was which by playing the game.
Booting in half the time using an SSD provides a noticeable significant difference.
But it all depends on personal preference of where your priorities lie taking into account value and diminishing returns. IMO on a 1080p 60Hz screen, the improvement going from one 780 to two 780s has such limited visual improvement that there is no value to it. Lot's of cost for very minimal actual visual improvement. If someone offered you four of Girls Aloud for the night for £500 then said you could have all five for an extra £3000... yes there's a slight improvement, but it's not worth it.
If you're moving up into the 120 or 144Hz screens or 1440p resolution then the actual visual improvement increases and thus makes it more value for money to get the 2nd 780. But I doubt most people would look at a game running at 60Hz on a 1080p screen on mostly max settings with no AA and think, "this looks rubbish, I need another 780".
But I know you like your SLI 780s so we'll leave it at that
EDIT... plus this build isn't just for gaming...