Not sure what to get/upgrade

[robwigan]

I currently have 2 year old system I use for gaming

I have a 280x msi and crappy iiyama monitor I want to upgrade.

I'd like a free sync or gsync monitor and there's a great deal on a free sync monitor by AOC on over clockers but I'm not sure what card to get ideally I want to spend as little as possible, I'm hoping to sell my existing card and monitor to help fund the upgrades.

I don't know to get a used 780ti and spend more on a gsync monitor or get the good deal on the aoc free sync and amd card.

I want the best picture and performance for the money but don't know where to start

 

[robwigan]

Apologies

My budget ideally wouldn't go much above £400

I have 650 watt power supply
I5 4670k that I haven't over clocked
8gb ram

I do like amd cards they do seem to consistently offer good price to performance ration he ever I'm not loyal to any I just want the best bang for the buck used or new

 

[robwigan]

The aoc one above with free sync how is it that is so cheap is the quality not as good and would I be better off getting something like the benq abovee