Perspective view moving with shovehand sees part of view live and part static

Nvidia geForce GTX970 4Gb the awesome card of the moment, very big holomark rating, using this since Oct 2014, not had this odd behaviour before…

Just started seeing part of my screen with a square or rectangular edge allow movement on perspective whilst most of it holds onto the last view I was looking at before I decided to pan, in a static non changing way. I am seeing my 3D world through a smaller portal.

Then somehow it realises what has happened and wakes up to the fact that I am panning and all is well…or I have to stop as it hasnt woken up and try clicking and panning again to get it to refresh.

What is happening ?

I also have now found it doing so in ortho, I zoom out and only part of screen sees a change in view, I have to click somehwre to see it update.

Surely its not 36 instances of a filleted edged lightening hole that is not a block instance, there is hardly anything taxing in this project.

I found in V4 that as soon as I had copy pasted and created a lot of rivet holes, it slowed down and acted up, but this is a 4Gb game changing card unlike the 1/2Gb 9800gtx, or is Rhino itself simply unable to cope if given a few copies of the same item ? This is nothing compared to work I have to do.