650W for a 3070Ti?

[Lairlair]

I have a Bitfenix Whisper M 650W installed in my PC, works like a charm to power the Ryzen 9 5900x + 1660 Super and the few other, less power hungry components.

 

I'm considering upgrading to a 3070Ti, and most of the PSU calculators say 650W are enough, but some say because of some energy spikes, it's safer to go with at least a 750W PSU. Can anyone confirm that? Is it okay to just upgrade and see if the PSU can handle it?

 

Btw I don't do any overclocking

 

Thankssss

[jaslion]

It's a good unit and worst case it just shuts down the computer. So you can try.

[freeagent]

At least a 750.. I can do 640 at the wall with mine..

[YoungBlade]

A 650W should be sufficient on paper. Even if you don't do overclocking, you can always use an OC tool like MSI Afterburner to turn down the power limit on the graphics card. Obviously, this can hurt performance, but a 3070Ti power limited to just 70% can easily outperform a 1660 Super.

 

If you're willing to get into the weeds a bit, undervolting is a great option for 3000 series cards. You can get the same performance at a greatly reduced power consumption. It will cost a bit of time to test for stability, but IMO it's very worth it. I run an undervolt on my 2060 Super most of the time these days, and I get slightly better performance (about 2% better) at reduced power consumption (10% less power) and reduced temperatures (5C cooler at max fan speed).

And worst case scenario, you need to buy a 750W or higher capacity PSU, which should only cost about $80-120. Compared to the $700+ for the GPU, that's not huge.

[YoungBlade]

36 minutes ago, freeagent said:

At least a 750.. I can do 640 at the wall with mine..

Don't you overclock your 5900X with PBO so it can draw up to 235W? That's 93W above stock. Even if your 190A EDC limits you to around 200W in most workloads, that's still about 60W over stock. So if you weren't doing that, you'd only pull 580W at the wall - probably a bit less at the wall even, as a 650W PSU would be more within its efficiency window at that point.

[ExalyThor]

Give your current power supply a shot. If it works, no need to change it. If your system shuts down when GPU utilization suddenly spikes up, first curse at Nvidia for designing 3000 series in such a way, then shop for a higher wattage unit.

[ExalyThor]

42 minutes ago, freeagent said:

At least a 750.. I can do 640 at the wall with mine..

If we assume a 90% efficiency, your system only draws about 580W. The other 60W is wasted by the power supply. You need to go over 700W at the wall reading to have your power supply work near 100%.

[Tan3l6]

The PSUs are rated at output power, not the juice from the wall, right?

[YoungBlade]

1 hour ago, Tan3l6 said:

The PSUs are rated at output power, not the juice from the wall, right?

Indeed. A 650W unit that's 80% efficient at 100% power draw will actually be pulling about 800W from the wall.

[Lairlair]

Thanks for all the info. Turns out that the person selling this 3070Ti at a good price was most likely a scammer... Too bad

[Tan3l6]

Just now, Lairlair said:

Thanks for all the info. Turns out that the person selling this 3070Ti at a good price was most likely a scammer... Too bad

pax vobiscum