Fedora is kind of slow, and suse is slow. So I'm thinking of trying centos(don't have money to use Red Hat). I just have a few questions.

My only needs are the newest kde and I'm going to be using a high end 3d program called Maya. I'm not sure if any knows what that is, but the web site can be found here: http://www.alias.com/glb/eng/product...ductId=1800001

my only question is can I upgrade kde 3.5.1, and is this going to be hard.

CentOS is a high-quality enterprise level distribution. They only use stable apps and components. If you want a stable distribtion with, maybe not the newest apps, but certainly the best ones, then go for CentOS. If you are one of those people who likes distros with "whiz-bang" new features and programs then go for Fedora. It's your choice. I found them to be both practically the same in my case. BTW, the speed is the same as Fedora.
As for KDE. Upgrading will be easy; don't worry about it and just try installing 3.5. If you run into any problems just tell us.

Best bet is to used optimized distros for KDE such as KANOTIX.

http://kanotix.com/index.php?&newlang=eng

This is based on debian, but is very well tuned for efficient memory usage as well as modify KDE to be faster.
check this news
It also uses KDE 3.5 will just need an apt-get update.

Although I was assuming he wanted a Red Hat based distro.
Just thought of this though, neither Fedora or CentOS are really optomized for KDE. Just look at the differences, you can tell they obviously spent more time on Gnome.