AW 17 120hz 780m OR AW 18 290x crossfire?

my m17 has been out of commission 2 out of the past 6 months, mobo replaced 3 times video card twice, dell has agreed to a replacement. below is their first offer
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Here you will find the suggested configuration for the replacement unit:


Dell Outlet Alienware 18 R1
Processor: Intel Core 4th Generation i7-4810MQ Processor (Quad Core, 6MB Cache, up 3.8GHz)
16 GB Dual Channel DDR3L 1600MHz (8GBx2) Memory
1 TB SATA Hard Drive (5400 RPM) + 80 GB mSATA SSD Caching Drive
Slot-Load Dual Layer...

AW 17 120hz 780m OR AW 18 290x crossfire?

AW 17 120hz 780m OR AW 18 290x crossfire?