You're probably using a value for the near plane that is too small. What near/far values are you using, and what's the size of your scene/objects?
I was using 0.005 for near plane, changed to 0.1, much better . Each block is 1x1x1.
With 0.1 there is still some very slight z-fighting, should I increase? Or will that cause it to clip too early?
Also, how does the near plane affect z-fighting?