I canno't share the scene but this is a screen shot of ma setup, 3 full HD sceen, one vertical, 3 windows, I instantly get almost 60 fps when I close the two side windows, other wise it seems to be lower than 10

So basically all i can guess is that it might just be too much to ask from your GPU.
At least it does not appear to be Blender specific.

Well, to me it's a bug ... when I minimize the two side windows, it's still slow and fast if I close them
Also there is no difference in CPU usage

Does this only happen with Blender?
I must admit i have no experience with multiple monitors maybe someone might have an idea.

In any case, we cannot do anything here really, this is specific to your hardware and software setup, plus the scene you are working on! Yes, having three HD OpenGL contexts is much more heavy than one - would not expect a gtx970 to be a limit here, though.

Other points to check/try:

• Does it happen with default startup blender (i.e. very light scene)?
• Check if the bug is reproducible on another, similar computer (this horribly sounds like over-heating or so).
• Give us your exact Blender, OS and GPU (including drivers) versions, as requested in the template!
• Ensure both your OS and drivers are fully up-to-date.
• Try the latest build from our buildbot.
• Try to start Blender in factory settings (--factory-startup commandline option) (this will ensure whether this is a userpref or addon issue or not).
• Try to tweak OGL settings in UserPreferences, System tab (window.draw methods, multisampling...).
• Try to tweak your GPU driver settings (e.g. try different values between 'performance' and 'quality' if you have such slider, etc.).
• Attach as text file here the report generated by Help -> System Info (do not paste it directly in comment).
• Try to place this dll next to your blender.exe (software OGL, will be slow, but will show whether this is a driver issue or not).

I don't think all those point are relevant.

My point is that blender seems to take some time to redraw all windows even when 2 of them are minimized

Other operation can be slow because, moving an object could affect an other object, a drived value in a node graph, change the curves in the graph editor etc...

But navigation only, should not, , it only affect the view where the mouse is. (except when camera is locked)

sorry... I was wrong, removing all my ad-don solved the "bug", I still have to find wich one.

Thank you