Hello, i'am going to buy Dell studio 1558 (i3-330M 2.13Ghz, 4GB DDR3-1333mhz, ATI Radeon 4570, 15.6"(1366X768)). And i think how NFS: shift would run on it, i saw a video on: http://www.youtube.com/watch?v=S8G_btO13As, but the video poster tested it on a i5-430M processor. So i wonder, would it run much slower on my i3-330M?
Why don't you install the game and run it to find out? Unless you don't have it currently.
The video card is a low end card. Don't expect to be playing at the best settings.
The system requirements for the CPU seem pretty low so I would hazard a guess at this game being more GPU intensive and your i3 not making much of a difference, if at all. Unless you enable physX. With an ATI GPU, all physX stuff will be rendered with the CPU. I think there might be a patch to help with that though.
The guy on youtube is running the game on the monitor's native resolution on medium settings with some things turned down and AA turned off. If he's legit, I would expect you to be able to do the same. He also said in the comments that he had to lower the resolution on order to get 50FPS.
PhysX is proprietary stuff Nvidia has. Some games use it for "nicer" physics effects. Because Nvidia owns it, ATI does not have access to the code. So they cannot design their cards or drivers to process physX. So only the Nvidia cards can render the PhysX stuff. Because the ATI cards cannot, as opposed to not working, physX is rendered by the CPU. This is much less efficient. My advice it to turn off physX if you do not have an Nvidia Geforce 8 series or better card. Some games do not allow this but you can still turn physX settings to minimum and it should be fine.