Add 4th GPU - All Hash Rates drop 40%

[BittBurger]

So I had 3 ASUS 280'x running and all three pushing at least 720 ..... it was wonderful.

Then I plug in a fourth GPU and they all drop to about 450 ....

Is it temperature?   May have gone from 67C to 70C at most ....
Is it a lack of power from power sources/motherboard?   

So strange that when four are attached, they drop ALMOST in half ....

Thanks

[BittBurger]

Figured it out.

Had to close all windows applications and exit Teamviewer.  Also disabled all the windows display extras and went back to basic boxes and solid colors.  Hashing back up in the 700's now.