If they are exactly the same price, I think the AMD system is might be a better deal( bigger hard drive)The warranty is only 90 days though. Whatever you decide I hope it works out well.They both have lots of RAM, but the ATI graphics may be better. I would look up the graphics chips online and compare. I would also compare the processors by reviews. But you may not have to, by the time you see this there will probably be way more expert answers than mine. If it were me I would look up the processors online too and review. or see if you could find user reviews on CNET, on the two Dell models. Also check out their tech support and warranty support too, from reviews if you can.
Good luck
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