PSU wattage requirement for new system.

[Linus Drop TIps]

I need help on choosing what wattage and efficiency I need for a system I am building. I am going to have a Ryzen 5 3600 overclocked to 4.2 Ghz and a overclocked RTX 3070. I know the 3070 has not come out yet but i'm sure a educated guess can get close to the wattage that this card will pull. The only restriction that I have is it needs to be a SFX or SFX-L PSU with a max width of 130mm.

[Yea, i use windows, W]

2 minutes ago, Linus Drop TIps said:

I need help on choosing what wattage and efficiency I need for a system I am building. I am going to have a Ryzen 5 3600 overclocked to 4.2 Ghz and a overclocked RTX 3070. I know the 3070 has not come out yet but i'm sure a educated guess can get close to the wattage that this card will pull. The only restriction that I have is it needs to be a SFX or SFX-L PSU with a max width of 130mm.

I mean, that is a good cpu and gpu combination, maybe try a online wattage calculator, but i would guess, get a 650-700W power supply, i could be wrong though

[Linus Drop TIps]

8 minutes ago, Yea, i use windows, W said:

I mean, that is a good cpu and gpu combination, maybe try a online wattage calculator, but i would guess, get a 650-700W power supply, i could be wrong though

Checked a psu calculator and it recommended a 650 watt gold rated psu. Thanks.

[Yea, i use windows, W]

2 minutes ago, Linus Drop TIps said:

Checked a psu calculator and it recommended a 650 watt gold rated psu. Thanks.

No problem, remember to get atleast 80+ gold cause efficiancy matters a lot in this case
Maybe mark the answer as correct too?  

[LIGISTX]

14 minutes ago, Linus Drop TIps said:

Checked a psu calculator and it recommended a 650 watt gold rated psu. Thanks.

A 650 really would be fine for that setup. the PC in my sig (9900k @ 5 GHz and a 2080 @ 2025 MHz) draws about 520 watts in game load. If I dial back the 9900 OC, I drop a good 30-40 watts. A 3070 will likely use the same power as my 2080 give or a take a bit, and your 3600 shouldn't be anywhere near the 9900k, and my 650 has plenty of headroom.

[Mateyyy]

What's your budget for the PSU?

 

37 minutes ago, Yea, i use windows, W said:

I mean, that is a good cpu and gpu combination, maybe try a online wattage calculator,

Most of them spew total nonsense.

26 minutes ago, Yea, i use windows, W said:

No problem, remember to get atleast 80+ gold cause efficiancy matters a lot in this case

Since we're talking about a ~300W load, efficiency really isn't as important since there won't be that much waste heat. When you start to get to 700W+, going with Platinum isn't a bad idea.

Assuming that's what you were referring to by "matters a lot in this case", since the efficiency rating tells nothing about the actual quality of a PSU.

[Yea, i use windows, W]

1 minute ago, Mateyyy said:

What's your budget for the PSU?

 

Most of them spew total nonsense.

Since we're talking about a ~300W load, efficiency really isn't as important since there won't be that much waste heat. When you start to get to 700W+, going with Platinum isn't a bad idea.

Assuming that's what you were referring to by "matters a lot in this case", since the efficiency rating tells nothing about the actual quality of a PSU.

Ahhh..... I understand now.. will remember in the future  

[Yea, i use windows, W]

18 minutes ago, LIGISTX said:

A 650 really would be fine for that setup. the PC in my sig (9900k @ 5 GHz and a 2080 @ 2025 MHz) draws about 520 watts in game load. If I dial back the 9900 OC, I drop a good 30-40 watts. A 3070 will likely use the same power as my 2080 give or a take a bit, and your 3600 shouldn't be anywhere near the 9900k, and my 650 has plenty of headroom.

Ah... Also according to nvidia, ampere will be more power efficient, due to the die shrink, and we did see the same results making ryzen CPUs more efficient when zen 2 came, so i agree with your comment

[Ankerson]

1 minute ago, Yea, i use windows, W said:

Ah... Also according to nvidia, ampere will be more power efficient, due to the die shrink, and we did see the same results making ryzen CPUs more efficient when zen 2 came, so i agree with your comment

 

They actually pull more wattage than the last generation. 

[Yea, i use windows, W]

Just now, Ankerson said:

 

They actually pull more wattage than the last generation. 

How?? 

[Ankerson]

2 minutes ago, Yea, i use windows, W said:

How?? 

 

The power limits are higher given the same cards from last generation to this generation.

 

An RTX 3070 is going to pull more power than the RTX 2070.

 

The RTX 3080 pulls more power than the RTX 2080.

[Yea, i use windows, W]

1 minute ago, Ankerson said:

 

The power limits are higher given the same cards from last generation to this generation.

 

An RTX 3070 is going to pull more power than the RTX 2070.

but how and why will 30 series pull more power? i mean, i think it makes sense now that i think about it lol

[Ankerson]

Just now, Yea, i use windows, W said:

but how and why will 30 series pull more power? i mean, i think it makes sense

 

The power limits are higher so they can draw more wattage.

[Yea, i use windows, W]

Just now, Ankerson said:

 

The power limits are higher so they can draw more wattage.

okay... thanks for the infoo!!

[OrionFOTL]

4 hours ago, Yea, i use windows, W said:

but how and why will 30 series pull more power? i mean, i think it makes sense now that i think about it lol

There is no "will". Ampere is already out, you know. 3080's and 3090's power consumption has been tested and you can look it up.

[LIGISTX]

21 hours ago, Yea, i use windows, W said:

but how and why will 30 series pull more power? i mean, i think it makes sense now that i think about it lol

They are more efficient, yes. But efficiency has nothing to do with power draw.

 

You can have two GPU's, one may be 5% efficient, one may be 90% efficient. If the 5% efficient card pulls 100 watts of power, its doing 5% of work and converting 95% of the power to heat. The 90% card may draw 200 watts.... It would turn 180 watts of power into work and 20 watts of heat. These numbers make literally no sense, most of the power your PC uses turns into heat, but this was just used to represent how the two are completely not related.

 

IF, and thats a big IF because its not actually the case here as 3000 series DOES draw more power, but if they drew the same amount of power, this would mean the 3000 series nets more FPS per watt used, and the only reason it gained that FPS is due to better efficiency. The 3000 series gains FPS due to better efficiency AND pulling more power. If it only did one or the other, it wouldn't be as good as it is.

[OrionFOTL]

4 hours ago, LIGISTX said:

You can have two GPU's, one may be 5% efficient, one may be 90% efficient. If the 5% efficient card pulls 100 watts of power, its doing 5% of work and converting 95% of the power to heat. The 90% card may draw 200 watts.... It would turn 180 watts of power into work and 20 watts of heat.

That's not at all how efficiency in graphics cards works. You're applying the term "efficiency" as it's used in PSUs and applying it to graphics cards, when it is not the case.

100% of power drawn by the GPU gets converted into heat and heat only. Energy doesn't disappear into some mysterious "processing work", as your last sentence suggests. ALL of it gets dissipated as heat, regardless of how much FPS the card can produce from it. 200W in, 200W out as heat.

More precisely, 99% of power drawn is converted to heat, while the rest is turned into a magnetic field (and in turn, kinetic energy) to move the fans, and involuntarily into a small amount of kinetic energy which vibrates the coils.

 

When people mention talk about "efficiency" in graphics cards, they solely mean how much FPS (or other measure of performance) they can produce per watt drawn, due to logic improvements in the GPU. Not due to how much power it can "turn into work" and "turn into heat", because that's not how conservation of energy works.

[LIGISTX]

6 hours ago, OrionFOTL said:

That's not at all how efficiency in graphics cards works. You're applying the term "efficiency" as it's used in PSUs and applying it to graphics cards, when it is not the case.

100% of power drawn by the GPU gets converted into heat and heat only. Energy doesn't disappear into some mysterious "processing work", as your last sentence suggests. ALL of it gets dissipated as heat, regardless of how much FPS the card can produce from it. 200W in, 200W out as heat.

More precisely, 99% of power drawn is converted to heat, while the rest is turned into a magnetic field (and in turn, kinetic energy) to move the fans, and involuntarily into a small amount of kinetic energy which vibrates the coils.

 

When people mention talk about "efficiency" in graphics cards, they solely mean how much FPS (or other measure of performance) they can produce per watt drawn, due to logic improvements in the GPU. Not due to how much power it can "turn into work" and "turn into heat", because that's not how conservation of energy works.

It’s not 100%, but it’s very, very high. I’m aware, just creating an analogous example. I think you missed the part where I said my numbers were completely made up and nonsensical, and that most of the power is turned into heat, but, I guess that’s the internet for ya.

 

Also, I exactly say it’s due to a increase in efficient and an increase in power draw. The card is getting for FPS per watt in, and it’s pulling more watts.
 

Obviously a GPU isn’t moving a mass, or creating noise (that is beyond a trivial amount), creating light (behind a trivial amount) or doing any other form of work, but that doesn’t mean the analogy isn’t helpful to understanding. Is it technically correct, no. But does it help explain why efficiency and power draw are two completely different concepts, yes. ¯\_(ツ)_/¯

 

Your correct though, I shouldn’t have used the term work. There is almost no actual work going on. And to add further clarification, a PSU doesn’t really do work, it converts whatever % of loss into heat, and the remaining energy is provided to the PC components at whatever stepped down voltage that rail is providing. But still, for the sake of understanding, it still shows efficiency vs draw are different concepts.