Upgrading sketchy PC

So I got this PC for free(thrift shop) and I'm looking to give it a good boost but I'm not sure exactly what route I should take with it, no plans on 4k or VR, just looking for solid 60fps and high/ultra at 1080p. Trying not to spend too much, probably $400 max.

CURRENT COMPONENTS:
AMD FX-8320 (3.5ghz octa-core)
Asus 750 Ti
Asus M5A97 LE R2.0
32gb ballistix sport 1600mhz
2Tb western digital green(I think)
cougar solution case
EVGA 500W W1
CRYORIG H7 cooler
2x 120mm fans + 85mm fan

I realize I cannot safely overclock with the mobo, so should I get a better mobo and overclock? A GPU (Gtx 960/970 or AMD equivalent)? Or convert it to an Intel machine? I also realize the PSU is on the lower end so I have to keep that in mind. Open to any suggestions.






 
Solution
Add these and it would make for a moderately capable medium expectation gaming machine. If you want to go slightly over a 400 dollar investment and go with a GTX 970 instead, it would be significantly better, but this would give you fairly capable results for the investment.


PCPartPicker part list / Price breakdown by merchant

Motherboard: ASRock 970 Performance ATX AM3+ Motherboard ($82.98 @ Newegg)
Video Card: Asus Radeon R9 380X 4GB Video Card ($209.99 @ Micro Center)
Power Supply: EVGA 750W 80+ Bronze Certified Semi-Modular ATX Power Supply ($48.99 @ NCIX US)
Total: $341.96
Prices include shipping, taxes, and discounts when available
Generated by...
That motherboard isn't even recommended for use with an FX 8 core chip. Thermals and power phase are not good enough. Before you do anything, you'd be well advised to replace it with a motherboard than can handle even a stock FX 8 core configuration.

The EVGA W1 PSU is not fit for use with a gaming card, not even an entry level model like the 750 TI. It is a mainstream unit, not intended for use with gaming cards OR with overclocked machines. The fact that you may not be looking to overclock is irrelevant. Both that board and PSU will be pitfalls that lead to troubles, likely why it ended up where it was in the first place. Get a decent board and a different PSU and you'll probably be at least ok.
 
Add these and it would make for a moderately capable medium expectation gaming machine. If you want to go slightly over a 400 dollar investment and go with a GTX 970 instead, it would be significantly better, but this would give you fairly capable results for the investment.


PCPartPicker part list / Price breakdown by merchant

Motherboard: ASRock 970 Performance ATX AM3+ Motherboard ($82.98 @ Newegg)
Video Card: Asus Radeon R9 380X 4GB Video Card ($209.99 @ Micro Center)
Power Supply: EVGA 750W 80+ Bronze Certified Semi-Modular ATX Power Supply ($48.99 @ NCIX US)
Total: $341.96
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2016-03-19 21:41 EDT-0400
 
Solution
With the board I listed, or alternatively something like the Gigabyte 970A-UD3P, MSI 970 Gaming or one of the medium to high end 990FX boards you should probably be able to take that chip easily to a full time 4Ghz, maybe 4.2-ish, with that H7 cooler. Any higher will probably require a better cooler. Although the H7 is extremely capable and is a high quality unit, it's still an entry level 120mm cooler and anything beyond 4-4.2Ghz is probably going to result in voltages being required for stability that will result in a pretty loud fan configuration under load.

With a Sabertooth 990fx board and a Noctua NH-U14S cooler I had my FX-8320 stable at 4.5Ghz@1.35v for a good long while before my recent upgrade to the 6700k, and it did pretty much everything you could ask for considering it's a 3-4 year old platform. For free, or mostly free, you can't really complain.