or can i live without it?
Well, that one cap isn't needed for your livelihood, so you can live without it. Your GPU, in the other hand, is different story.
There are no excess or surplus components on GPU. Each and every component is needed for GPU's operation. If you were to power on the GPU, it may not work. Or it could even fry itself since one vital component is missing.
You need to solder it back, given you have soldering iron and know how to do it. And even then, there's a risk that GPU might not work.
Btw, the capacitor that "fell off" is part of the NVDD. NVDD stands for the conventional core voltage, which sometimes is called GPU voltage. So, that capacitor is
very important. Especially since there is only one capacitor for NVDD.