I would go for the AMD build, because it provides you with 4 true cores as opposed to 4 virtual cores of the i3 (2 physical, each hyperthreaded).
Also get 4 GB DDR3 RAM with it. If you cannot afford it, take 2 GB now, next 2 GB later. Unless of course, you need the additional RAM for memory intensive tasks, in which case, by all means, get 4 GB DDR2. I understand you might be from India, where DDR3 prices are still stratospheric.
yes u r right,DDR3 is coslty but i can afford it NEways,,,but the motherboard of ASUS which i hv written dont support DDR3 but DDR2...there is not much difference in price though!!!so will it be ok for future to take 4GB DDR2 transcend RAM???what if i dont upgrade my system?will it go for future games?
I suggest you pick up one which supports DDR3.
The reason I recommend getting DDR3 is that for future upgrades, you could just reslot your RAM into the new pc. It might not be possible with DDR2 as support for it might not exist.
DDR2 is not such a bad idea actually. You could do fine with it for atleast 2-3 years with regards to games, apps, etc. Upgradibility is the only main issue here. The RAM might not work in a future platform, rendering it useless.
You have to weigh the pros & cons here to make a decision.