Ive stated in other threads to avoid purchasing a power supply until February or later if possible as tariffs should drop by then and new units will start arriving. If you need one today and looking at Amazon & Newegg, I would go with the Super Flower Leadex III 550W for $85. The platform is well reviewed and has a ten year warranty. It will deliver just as much power as that seasonic 650w unit when placed in a hot box (if not more and stay in spec). For cheaper you have the corsair cx550m for $65 after sale price and MIR. It uses a more modern DC-DC design to the S12iii. I would not go cheaper than that unit unless you need something to hold the line until you can save up for a better unit which according to the OP he has a 450w and something like the Nvidia 1660s would only push that unit to 50% of power.
You would still pay money for mediocre unit that may not be much of an “upgrade” from his current unit (I’m not sure of his exact make and model PSU other than it’s a 450w unit).
One - the unit is made by RSY not seasonic and if you know anything about Seasonic they love getting their units reviewed. I’m not knocking them as I’ve owned many of their units over the decades but their business model is based on getting rave reviews (caps in cables) and a cult following who screams “if it ain’t seasonic it’s trash” yet they refuse to send that unit out for any review tests (and it’s not RSY call on that).
Two - From PSU fans who have bought the unit and taken it apart; it uses a cheap LLC resonant designs with dual mag-amp, mediocre OV protection and cheap teapo caps hence why Seasonic refuses to send it out for testing.
Three - people are stating the 12v can go out of ATX spec when pushed. Without legit reviews the unit’s performance can’t be verified but would not be shocking as many cheap units have the same issue.
Four - I’ve seen that unit go as cheap as $35 with MIR so even at $50 it’s overpriced.
Corsair CX line or evga B5 are just better budget units for your money. Even the b3 line from evga, the superflower oem units not the RSY (it’s them again) made units as they suck and failed Tom hardware’s testing see their notes below
It looks like Super Flower(see my note below) made a huge mistake in its design, which poses a major safety risk. We noticed that the over-power protection triggering point is set way too high. Even under normal operating temperatures, one of the primary FETs in our store-bought sample, along with some other components, blew up. Either SF should set its OPP point much lower or use components able to handle higher amperage. We were also disturbed by the fact that, after the primary side shorted out, the PSU’s fuse didn’t blow. Every time we applied power, we saw sparks. Obviously, that’s a fire hazard.
note - SF design but RSY made as confirmed by EVGA as the reviewer bought four units with just the RSY unit having this issue