@hashmen
Sapphire TOXIC AMD Radeon R9 280X 3GB  cost $515
Sapphire TRI-X AMD Radeon R9 290X OC 4GB costs $740

Not at all twice the cost.  Configmyrig.com says the 280x gets 600 kh/s and the 290x gets 800 kh/s.
Litecoin info has high values contrasting from 770Kh/s vs 1002Kh/s.

So basically you are incorrect in both statements.