New PSU? I'm confused, HELP!

[Suckayo]

Hey y'all, 

 

Just recently snagged me a new rtx 3060 ti (at near msrp, yus!), I deleted old drivers from my amd gpu, install new rtx, add drivers and go to game.... Black screen, pc still on. It seems as though the PC just cut power to the GPU, no idea why. I realize that the psu I'm using is very old, maybe 10 year old 750 watt aftermarket with generic cheapy name. I assume this is the problem, so i use MSI afterburner to start undervolting, the lower i go the more my games run, only to ultimately black screen again. So now i switched back to my old Rx 570 and gonna game with this until I figure out the issue. My PC specs below (I realize some of these items dont mesh well, but with budgetary and availability restraints it was the best I could do in the last 2 years.)

 

Mobo a520m

Ryzen 3 3100 (will be updating soon)

16 gb ram ddr4 2666 mhz

750 watt old psu, name unknown, the tag fell off at some point.

And hopefully an rtx 3060 ti

 

I'm curious if I did something wrong, maybe i needed to do some bios stuff, maybe my gear is just old and crappy, maybe i need a new PSU. Let me know plz, HAAALP!

 

 

[Dukesilver27-]

I think most likely the PSU can't handle the transient spikes of your GPU, it may say 750W, but since there's no way of knowing whether it is true 750W, it might not push out 750W. Also, don't cheap out on PSU, it literally powers the whole system, if it blows then so is your whole PC. 

[An0maly_76]

Or it could be the janky practice of combining the wattage ratings of multiple 3.3 / 5V and 12V rails to fake a peak wattage rating. I've seen this on a Frontech that was supposedly 800W, but the true peak output was more like 300W.

[Anghammarad]

had a seasonic in the media pc which mase the gf 560 go black on full hd replay... swapped it out with a cooler master V550 anf smooth sailing from then on even while using the sames wattage.

[Suckayo]

Huge info, thank you all so much. I don't plan on cheaping out for sure, I'm thinking like a nice 650w