Right thanks for that.  It may be worth losing a little on watt efficiency to get the superior hashrate.  Also need to find the right motherboard.  Apparently the best ones are the ones where the cards are sat further apart so the temperature is easier to control.   

I’m hoping to start with kit to produce around 2000mhash/s.  I know its costly upfront, but the returns should be better in the long run surely as the algorithms become harder to crack?

Once I’ve got the value in the 1st setup I’d buy more and maybe look to lite and feather coins.  What about a pair of 6990s at 850 watt and 1740mhash/s?  I presume if I doubled up and had 4 of these running on a motherboard I’d get 3400mhash/ps but a 1700w power draw.  Apparently on http://ltc.kattare.com/calc.php that would mean $13 a day.

Does this sound right?

Why don’t sellers specify the mhash/s rate on their technical specs?