How much watts SMPS will be required for the AMD graphic card. Which Will be good SMPS for RX 570 ?
Here is a handy chart which works well.
It suggests a 500w unit for a RX570.
http://www.realhardtechx.com/index_archivos/Page362.htm
Of perhaps more importance is the quality of the psu.
Here is one list of psu quality:
Credit to @Starelementpokeand @Energycore for helping out with this long-awaited refresh of the old PSU tier list by Aniallation (who previously went several months without logging in), leaving the old list in need of help. This is simply an update of the list that was flawed in creation by the P...
linustechtips.com
It is not clear to me where your particular psu stands.
A cheap PSU will be made of substandard components. It will not have safety and overload protections.
If it fails under load, it can destroy anything it is connected to.
It will deliver advertised power only at room temperatures, not at higher temperatures found when installed in a case.
The wattage will be delivered on the 3 and 5v rails, not on the 12v rails where modern parts
like the CPU and Graphics cards need it. What power is delivered may fluctuate and cause instability
issues that are hard to diagnose.
The fan will need to spin up higher to cool it, making it noisy.
A cheap PSU can become very expensive. Do not use one.
If you are going to buy a new psu along with a RX570, look to Seasonic, they are always good.
Alternatively the GTX1050ti you referenced above needs no 6 pin power and would run just fine on your current psu.