PCB_new lag (ghosting) in kicad 4.0.7

I have this PC
17.3" IPS (1920x1080) Full HD/ Intel Core i7-6700HQ (2.6 - 3.5 ГГц) / RAM 16 ГБ / HDD 1 ТБ + SSD 256 ГБ / nVidia GeForce GTX 950M, 4 ГБ

and I had install lates Kicad 4.0.7 ( before I had old stable version)
Some times laes Kicad work slowly as you can see on screenshot ( This red dots its like lag…show the way Im moving components…when you place component its disappear.)

Also its crashes a lot of times, just shut down the programm.

What can be the reason of it? How to solve it?
If there would be any benefits to upgrading from 16GB to 32GB on my PC?

The important information missing here is:

  • What operating system are you using?
  • Do the default, opengl and cairo canvas behave the same? (Switch canvas via the view menu)
  • Does eeschema also show similar behavior?
  • Windows 7
  • I can not say for sure, becouse this lag not every time. For the moment it work fine.
  • eeschema work without lags

I noticed that sometimes if windows get an update, you would need to re-install Nvidia video drivers using a clean installation (perform a clean install to make sure that none of the previous driver settings interfere with the current one and cause conflicts)
The drivers are there but will not work correctly until a new installation