I've currently got a 8 gig 2080 and a 750W power supply. All works fine.

Considering since the prices are coming down a 3090.

Will a 750W power supply be sufficient?

CPU is I9-9900k, 32 gigs ram.

Thanks.

nVidia recommend a 750w PSU for the 3090, so should be ok if you're not overclocking. 750w definitely won't run a 4080 though.

Edited December 16, 20223 yr by ckyliu

34 minutes ago, ckyliu said:

nVidia recommend a 750w PSU for the 3090, so should be ok if you're not overclocking. 750w definitely won't run a 4080 though.

No it`s the other way round the 4080 pulls less power than a 3090 even the 4090 pulls less power than a 3090.

Note the GPU Power draw well over 300watts for the 3090.

RTX 3090 vs RTX 4080 vs RTX 4090 - 31 Games 4K + Ray Tracing & DLSS 2 Performance Comparison - YouTube

Edited December 16, 20223 yr by G-RFRY

I would not run a 3090 on a PSU rated at less than 1000W--and a good quality one, at that.

I've measured loads as high as 700W at the wall on my 10900K + 3090 system--I am certain that peaks are spiking considerably higher when it's loaded up like that.

I run a 3090 and lots of peripherals with a 850W power supply; no problems at all.

The minimum recommendation for a PSU with a Nvidia 3090 is 750 watts.  That's a minimum recommendation.  The 750 watt PSU in my current computer, which has a 3070 card, lasted about two weeks.  I replaced it with a 900 watt PSU, no problems since.  I'd say that a more realistic and safe minimum with a 3090 card would be 850 watts.

As Bob said, 1000 watt I would say. Power spikes are a thing and can trip OCP, OPP on lower powered units. If its an older PSU with capacitors past their best, even more of an issue. 

I run an EVGA 1000 watt for my EVGA 3090 FTW3. 

 

 

I also have a 1000W power supply and with an under volt in place I typically see my EVGA FTW3 3090 pull around 230 - 250 watts.

I am curious to see what my whole PC is pulling at the outlet, I’m going to pickup a tester to see.

I'm running a 4080 on an evga 850w comfortably.

I'm not very familiar with the 3090 though.  750w might be a little tight.

EDIT:  I went back and plugged in my P4400 Kill a watt because I haven't checked while running VR.  Peak watts 504.  Average while in VR (HP Reverb G2) about 420w over a 10 min oval around Boston area.  Addons used:  Flytampa KBOS, FSLTL, AAU1 Longitude (new G5000) beta, FSW C414 with dual TDS GTNxi's and heavy cloud themes (usually Scattered and/or a mix of Storm).  I just set my headset on my desk and had the mirrored screen so I can see what the headset is seeing.  Did a giant loop with all HIGH settings and 200 LOD at 2x time compression.

I'd say that's about the hardest test yet.  It's higher than I'd typically run VR.

In 2D (1440p) with same testing area, and max right sliders (using TAA with frame gen) I got a peak of 406w but average around 340ish.

The 4080 is large but it can't be too different from the 3090 - but I don't know.  So 500w PEAK with heavy VR usage....  I think we typically over equip our systems 🙂

Oh forget to mention what's plugged into this power strip:

2x LED monitors, X530 5.1 surround sound+woofer, USB3 hub with numerous peripherals, and my systems specs in sig - I've got 6 rgb case fans with one fan hub, and 2x m.2 drives, with 1 sata III 1TB drive.

Edited December 30, 20223 yr by ryanbatc

5 hours ago, ryanbatc said:

I'm running a 4080 on an evga 850w comfortably.

I'm not very familiar with the 3090 though.  750w might be a little tight.

EDIT:  I went back and plugged in my P4400 Kill a watt because I haven't checked while running VR.  Peak watts 504.  Average while in VR (HP Reverb G2) about 420w over a 10 min oval around Boston area.  Addons used:  Flytampa KBOS, FSLTL, AAU1 Longitude (new G5000) beta, FSW C414 with dual TDS GTNxi's and heavy cloud themes (usually Scattered and/or a mix of Storm).  I just set my headset on my desk and had the mirrored screen so I can see what the headset is seeing.  Did a giant loop with all HIGH settings and 200 LOD at 2x time compression.

I'd say that's about the hardest test yet.  It's higher than I'd typically run VR.

In 2D (1440p) with same testing area, and max right sliders (using TAA with frame gen) I got a peak of 406w but average around 340ish.

The 4080 is large but it can't be too different from the 3090 - but I don't know.  So 500w PEAK with heavy VR usage....  I think we typically over equip our systems 🙂

Oh forget to mention what's plugged into this power strip:

2x LED monitors, X530 5.1 surround sound+woofer, USB3 hub with numerous peripherals, and my systems specs in sig - I've got 6 rgb case fans with one fan hub, and 2x m.2 drives, with 1 sata III 1TB drive.

I'm generally with you on the overequipment of our systems and I find your findings very interesting and helpful as I'm about to get a 4080 too. Just want to add that there are short peaks that the killawatt usually will not see (because they're too short, but still high). Those also make the PC shut off.

That said, I'm on a 650W PSU so I will be able to provide more narrow data soonish 😄 I just have to convince myself a 4080 is worth the money.

I had decided to got to a 1000w from the 750w when a1300w with a good name became available during Christmas pricing for $40 more so i went with it. Future proofing. Also went with a RX 7900Xt video card. Very pleased with both.

On 12/30/2022 at 1:08 AM, rka said:

I'm generally with you on the overequipment of our systems and I find your findings very interesting and helpful as I'm about to get a 4080 too. Just want to add that there are short peaks that the killawatt usually will not see (because they're too short, but still high). Those also make the PC shut off.

That said, I'm on a 650W PSU so I will be able to provide more narrow data soonish 😄 I just have to convince myself a 4080 is worth the money.

I'm aware of those spikes but I have to tell myself - if there are such large spikes then perhaps I did not select a quality PSU.   It would be fun to buy a more advanced analyzer hehe.  But I'm comfy with these results (p4400 still plugged in I'll run for a month to see my kWh usage)

I have the 3090 with 1000W and no problems. 

As others have already stated, can it do it? Sure, but I wouldn't. Go with a 1000W supply, you need to have some headroom.

I've also seen over 320W in MSFS consistently.