I have a 144hz monitor and use a DP connection. I do not have this issue. Perhaps it is specific to particular GPU family or DVI connection in your case?
Just replaced both of my old 24" monitors with 2 new 27" ones,1 is the Benq XL2720Z 144Hz(using DP) and my secondary is the Benq RL2755HM (using HDMI),Just checked crimson,Primary GPU memory clock is sitting at 1250 idle,so I also am having the same result.Temps seem fine as well.Not sure If it is an actual issue,But otherwise everything else is working fine.
And I am loving the new monitors.
From what I was just reading around the net,This is pretty normal with high refresh rate monitor/dual monitor setups.