Which one should I get

Im getting a christmas present for a friend of mine-- a new computer system. The two systems Im looking at are both Gateways. One has the new i7 920 processor, the other one has the core 2 quad 9400, but the i7 only has 3GB of ram and the core 2 quad 9400 comes with 6GB. Everything else is the same, including the radeon 4850 video card. I dont think she's going to be upgrading the memory for some time, so which should I get for her?

How much of a performance difference is there between these two systems, based on the amount of memory and the different cpu's?

Here is the core 2 quad 9400 system from newegg with a 400 watt psu:

http://www.newegg.com/Product/Prod [...] 6883113080

Here is the core i7 920 system from best buy with a 500 watt psu:

http://www.bestbuy.com/site/olspag [...] 11424308-2