Constant loading for almost anything, very slow computer since xubuntu 11.04 was installed. Streaming and video is unwatchable do to extreme glitching

I have switched from windows 7 to Xubuntu 11.04. Windws 7 was smooth and flawless, Xubuntu is choppy and glitchy leading to wait times for almost every possible CPU calculation. Streaming is also very choppy, it loads quickly but the sound and video playback is pure garbage. this was never a problem with Windows 7 Unlimited, it was flawless. I just wanted to try Xubuntu but from my experience its pretty garbage.
Is there something that can be done to fix this. Is Xubuntu 11.04 a much more CPU demanding operating system than windows 7 unlimited? Even opening programs in the home screen takes so much loading that the mouse can even stops working till the window is loaded.