What upgrade to my computer will give me the most improvement with the least cost?

[slicedbread1991]

I built a modest gaming computer several years back. It's a bit dated now and it's starting to show with some newer games. I was wondering what part in my computer that I can upgrade/replace with the least amount of cost, but with the most noticeable improvements. If it's simply not possible let me know as well.

Here's my system.
CPU: Intel Core i5-2500 3.3 GHz
Mobo: ASRock Z68 Extreme3 Gen3
Ram: 2x4gb G Skill DDR3-1333
GPU: ASUS ATI Radeon HD 6870
HDD: Samsung Extreme SSD 120GB

 

[rockie_]

R9 280X and faster , at least R9 280/GTX 960

Good options: GTX 970 , R9 290(X)
HD 6870 - 2582 points , Pass Mark 8
http://www.videocardbenchmark.net/high_end_gpus.html

 

[SPgamer007]

+1^ a gtx 970/290x would be a great deal if you are playing on 1080p,otherwise get a r9 285 or 280x,