Upgrading my pc

[henry2911]

i have 2 x R9 280X's SLI
i5 - 4670k
RM 1000X corsair PSU
Z87 D3HP Gigabyte
16GB Ram

I want to upgrade my graphics card to a card that would be able to run 1440p at 144hz so I have the option to upgrade to a better monitor, but I'm not sure what card to get, I was thinking of the 1070 however I have a friend selling their 980ti oc gigabyte g1 edition for 250 to 300 £ but it's been used for a year and not sure weather I should just get a 1070

Help would be greatly appreciated

 

[Chugalug_]

Wait for the 1080ti, should be a fantastic deal if you can afford it, if not it will drop the price of 1080s anyway.
I have a 1080 and I can tell you 1440p is really demanding, even a 1080ti might not be enough for me tbh! 😛
I want a mix of good graphics settings and high FPS in those more intensive games like Arma 3 and The Witcher 3.