GT80: 8 Go RAM and GTX 970M vs. 16 Go RAM and GTX 980M

Hello.

I'm thinking about buying a MSI laptop.
I'm hesitating between these two:
MSI-GT80-2QD-046FR-Titan-SLI-18-4-Core-i7-4720HQ-Windows-8-1-8-Go-RAM-128-Go-SSD-1-To-HDD/w-4#bl=HGBPlsi4
MSI-GT80-2QE-045FR-TITAN-SLI-18-4-Core-i7-4720HQ-Windows-8-1-16-G...