Yes, you can have both together on the same PC.
Usually, most people use the SSD for the operating system (Windows, Linux, etc.) and applications (Office, game launchers, browsers, etc.) while using the hard drive for game and personal file storage since games tend to be rather large and large SSDs are very expensive while large hard drives are relatively cheap.
The only problem with that is that while that makes the OS and applications much faster, it doesn't do anything for game map, level and startup loading times, but it's still definitely a good option since those usually don't take THAT long anyhow, and a few seconds won't kill anybody while something is loading.
Storage media has zero effect on "FPS" anyhow, so that won't be...