i have an Alienware Area 51 pc with x-58 motherboard, intel core I7 processor 6 gigs ram upgrading to 12. I presently have ATI HD 4870 x2 video cards and was thinkming of upgrading to a Radeon HD 6970. Is it worth upgrading or does anone have any better ideas. i was told this upgrade wouldn't make a big differance, also if i did i have a 2.0 x 16 interface and the new card is a 2.1 x 16 will it still work?