Anoying temporary partial graphical glitch when making changes to mesh

[SIM-O]

when i move things (not including moving things outward) i get this weird thing where most of the faces I'm editing appear to be not shifting, while a few do. once i let go, and refresh the model by doing something like rotating it, it pops into place, good as gold. problem is, it's kind of vital that i know exactly whats happening to the faces as i pull them, not having to let go, move the model and repeat. it's pretty irritating.

EDIT: I found out that it only happens when i leave the program on for a while, or having other 3d accelerated programs at the same time. I don't suppose there's a fix for this?