Intel HD 3000 (Sandy Bridge) 3d games problem

This bug is your issue. Buggy intel drivers. There are some very ugly workarounds that I have tried myself that can make the artifacts go away but (in the case of minecraft, at least) do not help the screen flickering.

EDIT: Here's the workaround I crafted up. Firstly, you'll need a newer version of intel-gpu-tools to tweak some data. Go here to pick up a newer version. You may add the PPA but to avoid a lot of unnecessary updates I recommend just manually downloading the package through "View Package Details", then expand the dropdown entry for the oneiric series and download either the AMD64 or i386 package, depending on whether you have 32 or 64 bit. Install the package.

With this installed, you're going to make a crontab. This will run a command AS ROOT on boot. Run the command:

sudo crontab -e

in the terminal. Type in your password. It will ask you which editor to use. Just pick the default (nano). Scroll down to the bottom and on a new line enter the following:

@reboot intel_reg_write 0x9404 0x00001800

To save and exit, press control+x, type y, then press enter. Perform a reboot.

From now on the artifacts should no longer be there.

Iam currently using Ubuntu 12.04 and had the same problem. Here is what i do:

Install mesa 3d graphic library(I think this was the command, correct me if not)

sudo apt-get install libgl1-mesa-glx

Then install this library that lets mesa use texture compression

sudo apt-get install libtxc-dxtn-s2tc0

No extra ppa needed. I test it with Amnesia an Minecraft and both work perfectly.