What is the difference between zolpidem tartrate and zolpidem hemitartrate?

Not much: It is just the difference in the binder, the active ingredient is identical.

The same: Zolpidem tartrate is also known as zolpidem hemitartrate which is the actual form of the compound, a salt containing 2 drug molecules and one tartaric acid molecule zolpidem is commercially available as its hemitartrate salt of formula 2 having a 2:1 ratio of zolpidem base to l-(+) tartaric acid. The hemitartrate salt of zolpidem.