Best budget card for occasional triple monitor gaming 2018

[md.abu]

I plan to buy a new GPU, I don't expect to max any new games at ultra settings or anything above 60fps. Main purpose for my system is work with lots of tasks running and some occasional gaming, I currently have 2 1600x900 screens, will soon replace with 3 1080p screens. I want to buy a budget GPU that would be able to run 3 monitors in medium settings at around 50-60 fps. I don't mind buying older used cards as cex offeres 2yr warranty and already have a few vouchers.


I currently had in mind:
R9 290X 4G ~£200
GTX 970 4G ~£200
GTX 980 4G ~£270
GTX 1060 6G ~330(was 1st choice but price has risen due to crypto craze by about £70)

will 4GB be enough and will my CPU bottleneck?

(variant of each GPU will vary as will be sent as random from cex)

I currently have an R9 270X 2GB, it holds up pretty well with most games whenever I play on 1600x900 monitor, but with newer games it starting to become a bit choppy and fps drops to around 30fps in forza horizon 3 in low settings and GTA 5 I can play at around 40-50 fps in medium-high settings VRAM seems to fill up most of the time.

System specs:
CPU- i5 3470
GPU- R9 270X 2GB
RAM- 2 x 8Gb 1600mhz
SSD- samsung 840
HDD- Toshiba P300 2Tb

 

[md.abu]

MERGED QUESTION
Question from md.abu : "Best budget GPU for occasional triple monitor gaming 2018"

My system will be used mainly for work with lots of tasks running and some occasional gaming. I don't expect to max out every game at more than 60fps or anything. I plan to use 3 1080p displays and expect to run games at around 40-60fps on medium settings. My current R9 270X 2GB handles GTA V fine at 40-50fps(medium-high settings ) but forza horizon 3 at 30fps(lowest settings) on single 1600x900 display, for most newer games it runs out of VRAM and I need an upgrade before I get triple 1080p displays. I don't mind old cards as I'll be buying from cex as they give 2yr warranty and I already have vouchers.

I had in mind:
R9 290X 4G ~ £200
GTX 970 4G ~ £200
GTX 980 4G ~ £270
GTX1060 6G ~£330(was 1st choice but recent price spike)

will 4GB VRAM be enough and will my CPU bottleneck?


System specs:
CPU- i5 3470
GPU- R9 270X
RAM- 16gb 1600Mhz
SSD- Samsung 840
HDD- Toshiba P300 2TB