Very low FPS on newly installed Linux

[Watercat]

I recently installed Ubuntu 10.10 onto my HP Pavilion tx2500 and installed HoN. HoN was running fine for me with Windows Vista with the graphics settings on medium, but under Linux everything is constantly choppy even with everything on low.

ATI Mobility Radeon HD 3200
2.1 GHz AMD Turion X2
2GB RAM
1280x800


$ glxinfo | grep -i "opengl\|direct\|server\|client" && lspci | grep -i vga && uname -a
direct rendering: Yes
server glx vendor string: ATI
server glx version string: 1.4
server glx extensions:
client glx vendor string: ATI
client glx version string: 1.4
client glx extensions:
OpenGL vendor string: ATI Technologies Inc.
OpenGL renderer string: ATI Radeon HD 3200 Graphics
OpenGL version string: 3.3.10237 Compatibility Profile Context
OpenGL shading language version string: 3.30
OpenGL extensions:
GL_EXT_copy_buffer, GL_EXT_copy_texture, GL_EXT_direct_state_access,
01:05.0 VGA compatible controller: ATI Technologies Inc RS780M/RS780MN [Radeon HD 3200 Graphics]
Linux LinuxTablet 2.6.35-24-generic #42-Ubuntu SMP Thu Dec 2 01:41:57 UTC 2010 i686 GNU/Linux


I'm very new to Linux, so any help would be greatly appreciated. Thanks in advance.