Yes, you can upgrade.
You will always do better with a stronger graphics card, particularly with fast action games.
As above, one question should be is this a worthwhile upgrade?
Run YOUR games, but lower your resolution and eye candy.
If your FPS increases, it indicates that your cpu is strong enough to drive a better graphics configuration.
If your FPS stays the same, you are likely more cpu limited.
The guts of all GTX1070 cards come from the same source, namely Nvidia. The differences will be in the fancy coolers and the amount of factory overclock.
You mostly get what you pay for.
If one brand has better support where you live, that might be best.
On ssd, today, I would only buy Samsung 850 evo. They seem to be more...