Is thermaltake smart se 730w modular psu good enough for i7 9700 ,2x8gb ram ddr4,rtx 2070 super 8gb and asrock phantom gaming 4 motherboard ?If not please tell me a good psu but for a limited budget around 100-150 dollars,thanks.
I often find good buys for EVGA PSUs on Ebay. In all honesty, I do believe you could go as low as 600 watts with how efficient on power these devices are nowadays. Your RTX 2070 should only use about 250 watts if you overclocked it quite ridiculously and your CPU is rated for 65 watts at baseclock. This should mean around 100 watts at a modest overclock (although I don't know how far you have overclocked it). The rest of a system with a couple hard drives can be estimate at around 100 watts safely, so your entire system should only use 450 watts at full bore. You could go even as low as 550, but 600 is a generally safe bet.
It's not really about wattage when it comes to cheap PSUs its more about consistent power delivery. Why put a close to a thousand dollars worth of PC parts behind a cheaply made PSU. A good PSU will generally run between 80-120 USD.