I am relatively new to Ubuntu. I saw my friend's PC running Ubuntu and tried it out of curiosity.
I started with 10.10 on my old PC with an nVidia 7300GS graphics card. It would occasionally freeze but other than that it was all good. (I was using the proprietary drivers)
But a month back I bought a new one (AMD X4 955BE/ 8 GB/ Radeon HD4250) and dual booted Win 7/ Ubuntu 11.04.
The issue is that the video performance is absolutely horrible. Even standard definition videos are unwatchably choppy. This is huge deal breaker for me, since I use my PC mostly for watching movies. I downloaded the proprietary drivers but it seemed like they dragged down the performance even more.
I also installed 11.04 on my friends laptop ( A dual core with Intel HD graphics and 2GB RAM), and it works like a dream. My friend says that she hasn't had to login to Windows 7 once in the last three weeks. 1080p videos play just fine without the need for any proprietary drivers.
I would like to know if there is anything else that I can try, because I really like Ubuntu and would like to have to login to windows only when I absolutely have to.
PS: I am using the Ubuntu 11.04/X64 whereas the one on my friend's laptop is the 32 bit version.