Question Transient spikes

[hunterczech]

Hi.

I would like to know if GPU power spikes during PC boot-up and if so will it mind when the power supply might not be fully capable to handle GPU?

I bought 5070ti and I have very high quality, yet 6 years old 650w seasonic focus gold plus. Didn't try it yet with this Gpu as it still didnt arrive but I want to know in advance so I don't mess up PSU or the GPU.

I'm planning to undervolt the GPU so the PSU can keep up just fine however I don't know if the PSU is at risk during Pc Bootup? Can it fry itself and the GPU?

I don't know whether or not to buy new Psu. Will the PSU handle undervolted 5070ti?

Just fyi, 5070Ti is 300W tdp GPU that can spike to up to 370W.

 

[Lutfij]

I bought 5070ti and I have very high quality, yet 6 years old 650w seasonic focus gold plus. Didn't try it yet with this Gpu as it still didnt arrive but I want to know in advance so I don't mess up PSU or the GPU.
You should be looking at a 850W unit for headroom, using this as a baseline;
https://www.techpowerup.com/gpu-specs/geforce-rtx-5070-ti.c4243
to add, a 6 year old unit will not output the same amount of power as it did when it was brand new.

 

[hunterczech]

I bought 5070ti and I have very high quality, yet 6 years old 650w seasonic focus gold plus. Didn't try it yet with this Gpu as it still didnt arrive but I want to know in advance so I don't mess up PSU or the GPU.
You should be looking at a 850W unit for headroom, using this as a baseline;
https://www.techpowerup.com/gpu-specs/geforce-rtx-5070-ti.c4243
to add, a 6 year old unit will not output the same amount of power as it did when it was brand new.

Thanks for answer. Techpowerup states 700W PSU as a recommended wattage. I thought that with some undervolting it would work with 650W but i'm not sure if its safe to try. So you think its better off just straight away go and buy new one? So I suppose its dangerous to try the old one? I've heard much crazier cases than mine where people ran 4090 on 650w psu just fine.

 

[Misgar]

So I suppose its dangerous to try the old one?

I doubt your new GPU will pull full power continuously for 5 to 15 seconds at startup. Most GPU transients are just that, namely very short duration current spikes in the order of milliseconds. The bulk (primary) electrolytic and secondary (smoothing) capacitors should have sufficient charge reserves to cope with GPU transients at startup.

This review shows the 5070 Ti consumes around 20 to 25W when idle. It doesn't show startup currents, but I'd expect them to be similar to idle. It's only when you start to stress the card (Furmark) that you see high power demands around 300W, with spikes up to 360W. Immediately under this graph, TechPowerUp mentions minimum PSU 650W.
https://www.techpowerup.com/review/asus-geforce-rtx-5070-ti-tuf-oc/42.html

Personally, I'd try the 5070 Ti on the old Seasonic PSU if that's all you have, but I'd replace it ASAP with a new 750W or 850W unit. After 6 years of use, I'd leave the Seasonic in an old system and treat the 5070 Ti to a new power supply.

You don't state what processor you're pairing with the 5070, but unless the CPU, mobo and drives need another 300W of power, your 650W Seasonic should cope for the time being. I wouldn't advise any long term stress tests or all night gaming sessions, but I doubt you'll ever see more than 500W an AC mains power meter when stress testing. That still leaves a notional 150W of headroom on a nominal 650W supply.