Does the FAH GPU client run the same WUs as the regular FAH client?
No, the GPU will run a set of WUs specially constructed for the FahCores new functionality. While the FahCore_10 WUs use the same file format as Gromacs WUs, the scientific code that performs the calculation is different and the WUs for FahCore_10 will yield incorrect results if run with Gromacs (and vice versa).