Is this too heavy?

I’m working on a portfolio website and have an animation for my introduction page. But it seems to go reaaaally slow on a older pc (AMD 750Mhz). On my AMD 2600+ it’s acceptable. I want to know from you guys how the animations run on your computers.

http://www.pixilated.be/beta

And also, do you guys think it’s necessary to keep into account the users with slower computers? (not that that’s are my target audience)

Thanks a lot!