@marvell1
That is a misconception.
What matters is $/GH and operational costs aka $/GH/m.
Increasing the hashrate lowers $/GH and can lead to a faster ROI, especially if your $/GH/m is low (aka 5ct/kW/h including hosting).
hmm thanks for the information I might have to rethink things then
Just look at the difference between your numbers:
at 4.1 TH at 2600WATT actually running the numbers provides a better hash/Watt number than 4.5 TH at 2900WATT
you gain 400GH @ an extra cost of 300W. That's still only 0.75W/GH, which, unless you have some crazy expensive electricity/hosting rates, is worth mining for a long time to come.