Performance with Sandy Bridge video card

[Alessandro Crismani <alessandro crismani gmail com>]

Hi everybody.

(This is a summary from an Arch Linux forum post, but I find I might
find better solutions here).

I am using Gnome Shell and I have recently bought a Thinkpad T420s,
which is equipped with an integrated Sandy Bridge video card. I am
currently running Arch Linux, with Gnome 3.0.2.

I've had tearing under 2.6.38 and the performance have been improved by
installing 2.6.39.

However, I still have tearing when watching movies and I still have
visual artefacts (they are highly visible by hovering and unhovering the
workspace selector in the overview). Furthermore, both with 2.6.39 and
3.0-rc1 from kernel.org mainline, the shell sometimes doesn't perform
well. In particular, the hot corner doesn't always react, when I select
windows in the overview I have an horrible lag before leaving the
overview, dragging applications from the dash to the workspace lags as
well and I experience a delay between clicking a button on the panel and
seeing its pop-up menu.

Some info on software installed (where pacman -Qs reads as "what version
of ... is installed on my system?")

$ pacman -Qs mesa
local/intel-dri 7.10.99.git20110531-1
    Mesa DRI drivers for Intel
local/libgl 7.10.99.git20110531-1
    Mesa 3-D graphics library and DRI software rasterizer
local/mesa 7.10.99.git20110531-1
    Mesa 3-D graphics libraries and include files

$ pacman -Qs intel
local/xf86-video-intel 2.15.0-2 (xorg-drivers xorg)
    X.org Intel i810/i830/i915/945G/G965+ video drivers

$ pacman -Qs intel (gives long output, that contains)
local/xorg-server 1.10.2-2 (xorg)
    Xorg X server

You can see that Mesa is from the 7.11 branch, the Intel driver is the
latest stable one.

Any suggestions? Anyone having similar problems? Should I report the bad
performance somewhere? Should I build some packages with strange flags
(like full Gallium or whatever it is to have better 3D performance). I
googled but I couldn't find anything useful.

PS: I'm an not used to graphic problems, so I might have said stupid
stuff along this lines, please forgive me :)