Graphics card and PSU

Solution
Then it may be worthwhile investigating what the recommended PSU wattage is for the reference r9 290x. With respect to the MSI card I linked above as a random example, it has a 250W consumption but this does not change MSI's recommended minimum 750W rated PSU. As a matter of interest I sometimes use this site as a brief check: http://www.realhardtechx.com/index_archivos/Page362.htm

A good quality but slightly lower wattage PSU may be able to mitigate the high demand better than a low quality but higher wattage PSU. Personally, I wouldn't take the risk.
Given the majority of members here recommending a good power supply for a PC (a bad one can mean a lot of damage) I would anticipate the answer to be no.

If I'm reading it correctly, that power supply is rated 600W. This MSI r9 290x graphics card has a 750W minimum recommendation: https://www.msi.com/Graphics-card/R9-290X-Gaming-4G.html.html#hero-specification

At the very least it can't provide the power that particular card requires.
 
Then it may be worthwhile investigating what the recommended PSU wattage is for the reference r9 290x. With respect to the MSI card I linked above as a random example, it has a 250W consumption but this does not change MSI's recommended minimum 750W rated PSU. As a matter of interest I sometimes use this site as a brief check: http://www.realhardtechx.com/index_archivos/Page362.htm

A good quality but slightly lower wattage PSU may be able to mitigate the high demand better than a low quality but higher wattage PSU. Personally, I wouldn't take the risk.
 
Solution
The tricky thing here is the 290x is a power hungry card. It's is going to use a lot of power under load, do not underestimate that. The FX 4300 uses another 95W in addition to the card, both from the 12V output. Not only that, but you don't want your power supply running at anywhere near full load all the time, you want some head room. So I would take that 750W recommendation seriously with this particular CPU/GPU combo.