My current configuration:
CPU: Intel E5200 @ 3,75 GHz (cooler: Thermaltake V1 )
MOBO: G31M-ES2L
RAM: 2 GB, 800 MHz
GPU: nVidia 8600GT (256MB)
HDD: 500GB + 1TB + 1TB
PSU: Seasonic S12II-380W

Currently I'm driving on 1280x1024 monitor, settings: everything max, except antialiasing set to 4x
I realised my computer is slow at CAD fun race (I got only like 5-15 fps) drawing a lot of dust, cars, etc
when driving on demo I got like 50 fps at start grid, and after constant 75 fps (coz I see cars only in mirrors :P)

I soon planing to swith to 1920x1080 monitor, and also I would like to use 8x antialiasing.
What do you recommoend me to upgrade? (probably GPU(which one)?)

Also when I try to run two LFSs simultaneously, my computer frezzes for a few seconds (black screen), and then got msg "display driver stoped responding..."
, lost conection to host,... this is probably due to lack of GPU memory ? (I have all high resolution textures installed)

My current budget for PC upgrade is about 150 euro

I would suggest a gtx550ti or a ati radeon hd 6770 for the gpu and if you have some money left maybe some more ram.

Thanks Henry for reply Before I thought something from range 5670 to 5750.
Just checked 6770 can be found here for about 95€ , and 5750 for like 70 €.
What do you think about 5750, will it be enough or I should go with 6770.

Just go for the 6770, it's faster and only marginally more expensive. I think a newer card will last longer as it will be supported for longer aswell.

When it comes to performance, the cards both should do the job fine.

Also keep in mind LFS is more CPU then GPU demanding. So I think with one of these cards you would be bottlenecked by the CPU.

You might be able to get away with a gtx560 or a ati hd 6850 aswell and they will be able tu run almost anything you throw at them. But i dont know hom much they cost where you live, but here they are about 150ish.

Quote from Bose321 :

Just go for the 6770, it's faster and only marginally more expensive. I think a newer card will last longer as it will be supported for longer aswell.

When it comes to performance, the cards both should do the job fine.

Also keep in mind LFS is more CPU then GPU demanding. So I think with one of these cards you would be bottlenecked by the CPU.

+1