upgrade my graphic cards

[rimartic]

hi
i have 2 vga card's of sapphire R9-270X OC
in crossfire mode
is it right to change them with one R9-390X ?
and still im looking for a good site or app that could give same answers about comparing single and cross or sli mode to gather
there are many sites telling you about vga's but what about comparing multi cards with single cards?!

and at last , witch single card should i buy to be arround 25% more powerful than my cards?

 

[frank_hnd]

for 1080p gaming I would remain with your config. are you having a bad experience with CF?

if I was thinking about moving to 1440p I would get a GTX1070.

 

[smorizio]

the older 390x is not a card now that you should look at. with the newer 480x and the newer nvidia gpu that are a lot faster then the older gpu and use less power is a plus to upgraders and buyers.
https://www.youtube.com/watch?v=ksN3VMkutQQ&html5=1
jsut replacing the older 270 with 480. or the newer 1070 will give your gaming rig a boost. it comes down to cost.
if you want a big boost in games go with 1070 sli.