The prefect upgrade for the R 290 is a RX 570 8Gb as for the price , It gives you a 120watt package with the same Fire Strike score as your Hawaii , all the tech they learned is about $150 as I liked the side step as to scale down but gain in memory size and power usage as to be paired with a 65watt cpu and I feel it has life as AMD is always picking speed up in the drivers.
RX 580 8Gb for $169 is like buying a dream in AMD tech with those games as I also own one of those that replaced my 290x as I can wait it out for Navi as noting 6Gb is interesting to me .. Vega looks nice but I like the small power usage for my 1080p panel for now.
Xeon X5660 @4.2Ghz
EVGA x58 3way Sli rev 1.2 bios 83
OCZ Gold ram 6 Gb
Corsair 950 watt powersupply