Understand that somtimes newer versions of this programs (furmark) are more demanding than before.
Be sure you are comparing apples to apples (ie same version)
Personally, i went from using my ips display to my buddys crappy 22 inch Acer monitor that he bought for $80.
Frankly, you can even look at a solid color on the screen without seeing different gradients of it due to its terrible viewing angles.
This is just one radical instance, i've seen lots...
Also, don't forget that you have settings on your gpu too (either nvidia control or catalyst control)
I at first had a huge problem with the same monitor but after playing with both the monitor setting and gpu setting, it's a farkin beautiful screen.