What GPU are you using? According to the Gerasim project two HD 7850/7870s. These are discrete GPUs, My A8-3820 does not have a problem either as it is coupled to a discrete HD 6670.
But my i7-3770 and my Athlon 5350, both running only with their intenal graphics -respectively an Intel HD 4000 and an AMD Kalindi/HD 8400-, have the problem that their GPU part does not get detected by the Gerasim app. The Gerasim project itself has no problem seeing these GPUs.