can someone recommend a solid upgrade strategy?

[MegaHavok]

PC:
R9 280X
FX 8350
8gb DDR3 (2*4GB 1866) Corsair vengence
650W corsair modular PSU
GA-990XA-UD3

A complete overhaul or just a GPU or CPU upgrade?

 

[SgtScream]

What do you plan to use your upgrade for and what's your budget?

 

[MegaHavok]

What do you play to use your upgrade for and what's your budget?

killing floor 2, cs go, elder scrolls

budget £100-£200

 

[Eximo]

Not much to recommend, you have a decent GPU and an adequate CPU with no upgrade path.

A new GPU would add a little bit, but going from an R9-280X to anything current gen with that budget would be more of a side grade. RX570 might be worth a look, but wouldn't be a vast improvement over what you have.

But really the rest of the computer would need to be replaced to improve gaming performance further.

 

[SgtScream]

I play all those games except scrolls and my honest opinion is that you don't need any upgrades for those games. Save your money for when you really need it. That way you'll have more money to spend on new hardware in the future.