Is this power supply to old?

if a PSU goes, it can potentially take your whole system with it .. don't skimp on your psu... I'd recommend getting a quality 80+ gold 600w or better that can stick with you through several upgrades. Your rx580 can pull upwards of 300w on it's own when under load. (based on review I just read comparing the RX580 do the new 5600XT).

Any PSU can die at any time and do potential harm to your PC.. but having 1 bullet as opposed to 5 bullets in your six shooter while playing russian roullette .. your playing with 5 bullets.

Your system shouldn't need more than 400W, but to be safe for future upgrades, I would recommend aiming for a good quality 500W supply.
If you're in a budget and looking for as much quality as possible, I would look at Corsair CXM series ([URL=https://pcpartpicker.com/product/3hkwrH/corsair-power-supply-cp9020102na]Corsair CXM 550 W[/URL]) as well as be quiet! Pure Power 11 500W ([url=https://pcpartpicker.com/product/cTfhP6/be-quiet-pure-power-11-500-w-80-gold-certified-atx-power-supply-bn901]non-modular[/url], [url=https://pcpartpicker.com/product/qpvbt6/be-quiet-pure-power-11-cm-500-w-80-gold-certified-semi-modular-atx-power-supply-bn297]modular[/url]).

BTW..

Could you recommend a brand of power supply that is worth its money??

For those specs it should be fine. So long as the fan isn't ramping up and the air
coming out the back of the PSU isn't more than mildly warm under load it means
the PSU isn't overloaded. If the PSU fan is pulling air from inside the case flip
it so it draws air from outside as it is intended to be used.

I may also ad, Ray its not noisy at all. It was very quiet.