How / why does a 7800X3D cause double+ power use from a GPU?

All Discussions > Steam Forums > Hardware and Operating Systems > Topic Details

ploppo 26 Jun @ 12:07am

I am someone considering a new PC and the 7800X3D came to my attention as a power gaming processor that uses low power. However, I have noticed a glaring oddity.

I watched a video of a 7800X3D vs an i5 14600K and was astonished to see the RTX 4090 tied to the 7800X3D sometimes using more than double the wattage when the 7800X3D was outperforming the i5 14600K. Here is the video (11th June 2025):

https://www.youtube.com/watch?v=6C6aUc22VQU

How does the 7800X3D cause a GPU to use more than double wattage? It happens a lot in the video where the GPU is using blatantly more watts.

Surely the savings on the low power draw of the 7800X3D is offset by the higher power draw of the GPU?
How does the 7800X3D cause a GPU to use more than double wattage?

HOW/WHY DOES THIS HAPPEN?

https://ibb.co/7Jb35QJ0
https://ibb.co/wNGZcK8X
https://ibb.co/bMGwpGs0
https://ibb.co/TBHVV7TN
https://ibb.co/6JrDdwk7
https://ibb.co/cKt8RdbL
https://ibb.co/qYm8sW4F
https://ibb.co/HDxXXRKF
https://ibb.co/RkNkhtRk
https://ibb.co/5X28rQgr
https://ibb.co/wNhNNZt9
https://ibb.co/Q74nBXC7

< >

Showing 1-11 of 11 comments

Bind0fGod 26 Jun @ 12:16am

probably because the 7800x3d is in the top 5 gaming CPUs and serves the 4090 far quicker than the i5.

Simply put, the 4090 is being utilized to its upper limit because the processor is pushing it further

Edit: I I watched through that vid and screens and its as I thought . The GPU utilization is always higher when the wattage is,

If you really want to prevent this you can lock the framerate.

In the vid there's a few times where it's the opposite btw, and the i5 is causing the 4090 to use more power.

PS: you can also undervolt your GPU to save even more wattage , often with no performance loss.

Last edited by Bind0fGod; 26 Jun @ 12:17am

ploppo 26 Jun @ 12:21am

Originally posted by Bind0fGod:
probably because the 7800x3d is in the top 5 gaming CPUs and serves the 4090 far quicker than the i5.

Simply put, the 4090 is being utilized to its upper limit because the processor is pushing it further

Edit: I I watched through that vid and screens and its as I thought . The GPU utilization is always higher when the wattage is,

If you really want to prevent this you can lock the framerate.

In the vid there's a few times where it's the opposite btw, and the i5 is causing the 4090 to use more power.

Hi, thanks for the answer. It is true that the i5 used more power every so often - but the swing difference is blatant with the 7800x3d in terms of total watts.

Your answer is interesting because, for me, it changes how efficient a CPU truly is if a GPU is drawing more power. I never really took into account balancing a CPU and GPU in terms of the combined power used.

I have watched many comparison videos over the years, but this is the first time I took note of the watts a GPU was using

Bind0fGod 26 Jun @ 12:26am

Originally posted by ploppo:
Originally posted by Bind0fGod:
probably because the 7800x3d is in the top 5 gaming CPUs and serves the 4090 far quicker than the i5.

Simply put, the 4090 is being utilized to its upper limit because the processor is pushing it further

Edit: I I watched through that vid and screens and its as I thought . The GPU utilization is always higher when the wattage is,

If you really want to prevent this you can lock the framerate.

In the vid there's a few times where it's the opposite btw, and the i5 is causing the 4090 to use more power.
Hi, thanks for the answer. It is true that the i5 used more power every so often - but the swing difference is blatant with the 7800x3d in terms of total watts.

Your answer is interesting because, for me, it changes how efficient a CPU truly is if a GPU is drawing more power. I never really took into account balancing a CPU and GPU in terms of the combined power used.

I have watched many comparison videos over the years, but this is the first time I took note of the watts a GPU was using

It's also worth noting that the 4090 is one of the most power hungry GPUs on the market.

But generally speaking the more powerful a CPU- the higher the GPU the utilization- the more power the GPU will use.

Lotta ways to control this though. As I mentioned, FPS locking and undervolting are always an option.

Or getting a GPU that's less power hungry.

You'll always need to balance CPU and GPU though for power and utilization
(I paired a 7800x3d with a 7900xtx. . )

Last edited by Bind0fGod; 26 Jun @ 12:28am

Bad 💀 Motha 26 Jun @ 2:20am

Any i5 + 4090 is pathetically dumb combo.
It's not that the Ryzen is doing anything or causing anything wrong there; it's that the i5 is holding the GPU back from performing like it could/should.

Also you could undervolt a GPU such as 4090 / 5090 and get the same performance as long as it's stable, but in the end using less power.

Last edited by Bad 💀 Motha; 26 Jun @ 2:22am

_I_ 26 Jun @ 2:33am

when cpu bottlenecked the gpu cant be maxed out

hawkeye 26 Jun @ 3:25am

Gpu power usage is dependent on fps, resolution and graphic settings. Higher fps -> higher power usage.

C1REX 26 Jun @ 3:38am

Originally posted by ploppo:
Surely the savings on the low power draw of the 7800X3D is offset by the higher power draw of the GPU?
How does the 7800X3D cause a GPU to use more than double wattage?

HOW/WHY DOES THIS HAPPEN?

https://ibb.co/7Jb35QJ0
https://ibb.co/wNGZcK8X
https://ibb.co/bMGwpGs0
https://ibb.co/TBHVV7TN
https://ibb.co/6JrDdwk7
https://ibb.co/cKt8RdbL
https://ibb.co/qYm8sW4F
https://ibb.co/HDxXXRKF
https://ibb.co/RkNkhtRk
https://ibb.co/5X28rQgr
https://ibb.co/wNhNNZt9
https://ibb.co/Q74nBXC7

Others already explained why it's happening but I will add that the 4090 can draw less than 100W while gaming if you lock to 60-144fps in such light games. There is no need for most people to run games at 600 fps, draw 5x the power and heat up your room during summer.
But with a better CPU you can run games faster when you want to.

Here is a good video explaining how the same PC can draw 650W or less than 200W with locked FPS.
https://youtu.be/WAmp9AHydgU?si=NbkB92wErky2nDGV

Last edited by C1REX; 26 Jun @ 7:26am

Monk 26 Jun @ 5:10am

Did you fail to notice the fps difference?

It's, a really odd comparison tbh, mid range vs the old king.

Illusion of Progress 26 Jun @ 6:17am

Originally posted by hawkeye:
Gpu power usage is dependent on fps, resolution and graphic settings. Higher fps -> higher power usage.

This is the answer right here. I glanced at the first half of your images and there's a large frame rate gap in almost all of them.

If you then wonder "why does the wattage go up disproportionately to the frame rate", it's because things aren't linearly efficient and you should never simply presume linear scaling in anything with PCs regarding performance or power use. Things tend to become less power efficient near the top end of their capability.

wesnef 26 Jun @ 7:24am

Yeah, it's not "why does the 7800x3D make the GPU use too much power", it's "the i5 is crippling the GPU so it can't do it's job."

#10

Bad 💀 Motha 28 Jun @ 4:11am

And if the CPU/ GPU is getting too hot as result of pushing both 100% then you need better cooling and properly and/or better adjust the fan curve for cpu and gpu. Never rely on the gpu auto fan curve, change it manually

#11

< >

Showing 1-11 of 11 comments

Per page: 1530 50

All Discussions > Steam Forums > Hardware and Operating Systems > Topic Details

Date Posted: 26 Jun @ 12:07am

Posts: 11

Start a New Discussion