How good is ATI 5870

well i am planning to buy this MSI GX660 gaming laptop with following specifications that are available in india. but as i am new to gaming i don't know for sure that if this is the right choice. also, there are some confusions that are there in the configuration of the system that i wanna get sorted b4 buying it. here are the specifications: PROCESSOR: intel core i5 460M, GRAPHIC CARD: ATI Radeon HD5870 with 1GB DDR5, CHIPSET: Intel PM55, RAM: 4GB DDR3(2GB*2), HARD DISK: 500GB sata@ 5400rpm, LCD: 15.6" HD Glare(1366*768)LED. There are 3 main confusions that i am dealing with right now. FIRST, is there any difference between GDDR5 and DDR5,coz on the website they show as this model has GDDR5 graphic memory but my dealer's configuration states it as DDR5 graphic memory. SECONDLY, the hard disk is running at 5400rpm & as i want to buy this laptop for gaming , does it will effect the gaming performance on a large scale or not as compared to 7200rpm. LASTLY, after checking out all the specifications of the system thati have provided earlier. what do you think of this laptop as a whole,especially in gaming performance. will it be able to run newest games (between 2009-2011) at high setting without any hitch?