I have noticed you were using customized drivers not provided on the Intel web site.
Please let me know if you already tried version 22.214.171.12475
I tried 2875 driver too, with same effects.
But, despite v.2897 driver (I currently use) is provided on Intel web site with respective status "current": http://downloadcenter.intel.com/Detail_Desc.aspx?lang=eng&changeLang=true&DwnldId=22182 Download Center , I'll try v.2975 again.
I made few screenshots as illustrations what I mean. Of course, still images don't show flickering.
This effect appears only in dark, shadowed scenes, but in bright scenes there is nothing like it.
2885 driver, balanced 3d settings and all other on defaults. This is a hardware failure?..
http://i52.fastpic.ru/big/2013/0105/d4/f40ceb4c245089abc3c5c3033629c2d4.png (ooo-h, anywhere on walls)
http://i51.fastpic.ru/big/2013/0105/74/1af0bc277f91131cb9684aa96a2f1b74.png (look at left curtain)
And yes, I tryed different drivers.
Can you try lowest settings in Metro 2033?
Looks like your iGPU is damaged.