3d performance issue in Ubuntu 12.10

[Ministry]

Hello.
I've a HP notebook (HP Pavillion dv6, with 4gb ram and onboard Intel graphic card).
I've recently installed Ubuntu 12.10 64 bit and Openarena 0.8.8 has very poor performances, even at lower details; this means jerky graphics, various glitches and so on.
I tried downloading both the unified version from the site and the dedicated version from the Ubuntu Software center, but they are identical.
I know I don't have a "monster pc", but the game - the same version of course - runs very well in Fedora 17 64 bit, even at higher detail level, "out of the box" without doing anything special.
What should I check?

[fromhell]

What does glxinfo report? Open up a terminal and type that. Doing so would be a very good start to determine if you have proper video drivers with hardware acceleration for OpenGL.

[Ministry]

This is what I checked out:

glxinfo | grep render

Code:

direct rendering: Yes
OpenGL renderer string: Mesa DRI Intel(R) Ironlake Mobile
    GL_NV_conditional_render, GL_ARB_ES2_compatibility, GL_ARB_debug_output,

lspci | grep VGA

Code:

00:02.0 VGA compatible controller: Intel Corporation Core Processor Integrated Graphics Controller (rev 02)

[Ministry]

Up!