Pan_Kara:
About the 3dmark score: I managed 5566 and you 4700. The only notable diference I see is the cpu. Mine is an MT-34. I used Catalyst 5.10a. Have you tried these? or did you use the ones that came with the laptop? Did you have the laptop plugged to the mains? Running on batteries affects performance.
About the overclock: did you use aTITool 0.25Beta8 ? I had some problems with artifacts, when I would use a certain combination of core speed and memory, it would give me artifacts, for instance: 390 core 370 mem (I'm making this up, I don't remember the values) would give me artifacts, but 425.25 378 would be ok.
i suspect that the core and memory speeds are related to each other by a multiplier of some kind. And I belive that ATITool does not respect this, hence, when you try some mix of speed/core speeds, you will get artifacts, even if you are not overclocking: try downclocking it and see!
I would do as follows: without touching the core speed, I would try to get the memory as high as you can. Then , I would reset the ram speed, and try to up the core speed until it shows artifacts. After that, you know more or less the limits of the hardware and can try the best combination of core/mem speeds.
Also, When you start to overclock, it is better to let the laptop run for a while in 3dmode to allow it to heat up. This will make the fans run at full speed. If you try to overclock as soon as windows boots, you may see artifacts, because the fans did not kick in yet, and the graphics chip is overheating...
