Will my computer really handle a Zsnes emulator... seriously?

[Peter_20]

So, I've got an own apartment a while ago, and I've got an own computer there, but I can't use the Internet (I'm visiting mother right now ), so I considered copying the Zsnes emulator from her computer over to my own computer at the apartment.
However, a few days ago I discovered that I actually had both the Snes9x emulator as well as a ROM of FF5.
I tried playing, and now the troubles showed up: everything SUCKED!
I tried to change the settings, but it was always this slow thing, and it updated very poorly.
Sometimes the chars seemed disfigured as well, because they updated unevenly, and that dragon in the opening sequence almost destroyed the speakers, because it sounded so freaky.
Nothing seemed to change this - everything sucked - so now I'm worried about what using the Zsnes emulator on that computer might lead to.
Does Snes9x just plain suck, or is my computer too slow?

The computer at my apartment is a Dell Dimension XPS R450, and it's from 2002.
It looks a lot like this: http://www.ce.cmu.edu/NewIcons/dell_...s_r_series.jpg