Bug Hunting

Following on from my other thread, can anyone give me a couple of clues as to what i maybe need to look into to sort a crash issue? I’m tweaking textures - trying to - and when i Shft+Z my GPU seems to be regularly crashing. this has happened a couple times even when i’m looking at restricted views, have subsurf turned off etc etc, so i’m not fully convinced it’s running out of memory. additionally, when i do a proper F12 render w/ more samples etc it completes no problem. Can’t seem to find the Blender crash log anywhere, is that supposed to be in the Blender folder?
i’m using the current 2.79 on Win 7 64bit.
TIA

sounds like a tdr delay issue. this happens when the gpu takes to long to do something, it crashes.

was thinking that but i’m sure i got some identifiable Event or something the last time i had those. Can’t think what it’s doing that would hang up the ShftZ viewport but not a full-on render calc though?