Graphics card

Your first port of call as noted above is to make sure you have the most up-to-date drivers for your hardware. Assuming that your card does actually meet the minimum requirements, you may want to consider changing the game settings. For example reducing the graphics value (i.e. from high to medium), un-checking the box next to certain attributes such as shadows, reflections and viewing distance will also reduce the pressure on the GPU. I remember years back when they released one of the Tom Clancy games. I was working in an electronics store and we had so many people coming in to complain that they'd queued for ages to get the game and despite having mammoth ATI cards, the game was either not working or very poor. That day we sold out of all Nvidia-based cards. Some people had spent upwards of £100 on an ATI that was hopeless for that game, yet the £30 Nvidia card worked perfectly fine. I've personally always stuck with Nvidia and i know a great number of colleagues and clients over the years who do the same. That being said if an individual has had a long-standing good service from ATI or any other brand/hardware i will not impose my own opinion. If it works well for you ... that's all that matters.

I don't know much about the games. But i can imagine your problem i suggest you to check that graphic card is properly working or not i mean the drivers of the graphic card are properly installed or not. Try to do any configuration part if there is any. I think when buying graphic you have checked the compactability again check this. If nothing works try to format and install a new operating system so that if there is any virus thats eats any RAM will be cleared and System will be ready to handel more and more programs. Please don't leave it because i am the person who thinks that we should make the computer work according to our will.

Try to download the latest drivers at http://ati.amd.com/ this may work for you. Need for speed undercover is the only game where u can see artifacts? If u can see them on every game,maybe is an hardware fault and/or compatibility issue.