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I have recently downloaded Minecraft to Ubuntu 12.04. It launches and plays successfully, however- the frame rates for the game are extremely slow. They never go past 9 fps and usually drop below 3 fps.
I have been a Windows XP user for years and have just recently switched to Ubuntu, so I'm not an expert with this OS. My video card is a Diamond Stealth s60 with Radeon 7000.
I don't know what other information you guys need but if you ask for it, and would please tell me how to get to it, I will tell you as soon as I can. Thanks for your help.