How do I calculate the wattage max consumption of my pc?

[IR76]

I'm figuring out what my wattage max consumption is on my pc for all my components and want to know what's the best way?

 

The ram doesnt tell me what it is in windows or BIOS so I'm guessing I'll need to open the pc up to look for model number 

 

I think I do the TDP for CPU and GPU but some say it's not nessecarily accurate so what do I base it on?

 

Once I have this info I can start adding in new parts and figure out what PSU I need

Any questions please ask thank you.

[mariushm]

For cpu and video card, you can look at reviews that say the power consumption for that part alone

 

I can tell you Ryzen on AM4 peaks at around 160 watts for the 5950x , AM5 may go a bit higher ...  Intel is a pig, can go to 300w or more, but now you see in the news that they all die prematurely.

 

For video cards, if it's one 8 pin connector, it will take max 150w + 75w from slot , if it's 2 8 pin ... 300-350w max

 

motherboards ... anything between something like 5-10 watts to 30-40 watts depending on chipset and how much bling you have

 

fans - 2-3w from 12v, water pumps maybe 10-15w from 12v

 

SSDs ... typically 1w or less when idle, maybe 4-5w when writing for long periods... a bit more on pci-e 5.0 drives

 

HDDs - around 6-10 watts depending on rpm ... half on 5v , half on 12v

 

RAM ... for DDR4 it was around 2-3w per stick per 8 GB  - ex 2 x 8 GB = ~ 4-5 watts.  DDR5 at high mhz may be a bit more. Usually powered from 5v or 3.3v, dc-dc converter reduces it to 1.35v or less.

 

Unless you get a 4080 or 4090 or high end AMD alternative, you'd probably be fine with something in the 650-750w range. 

 

If you aim for the absolute highest efficiency, you'd want to get something where the power consumption when playing games will be around 50-60% of the maximum capabilities... that's where the highest efficiency is on most power supplies.

 

But on modern power supplies, they're very efficient on a wider range ... ex they may be 92% efficient at 30% of their maximum output power, peak at 94% at 50-60% and then fall down gradually to 93% at 80% and then go down towards 90% at 100% output ....

 

These 1-2% differences are basically nothing.

 

[PDifolco]

9 minutes ago, IR76 said:

I'm figuring out what my wattage max consumption is on my pc for all my components and want to know what's the best way?

 

The ram doesnt tell me what it is in windows or BIOS so I'm guessing I'll need to open the pc up to look for model number 

 

I think I do the TDP for CPU and GPU but some say it's not nessecarily accurate so what do I base it on?

 

Once I have this info I can start adding in new parts and figure out what PSU I need

Any questions please ask thank you.

Simplest way is to go over to PcPartPicker.com, make your build, and check wattage

[noobwhoneedshelp]

16 minutes ago, PDifolco said:

Simplest way is to go over to PcPartPicker.com, make your build, and check wattage

was about to come and say this - beat me to it

[Agall]

31 minutes ago, IR76 said:

I'm figuring out what my wattage max consumption is on my pc for all my components and want to know what's the best way?

 

The ram doesnt tell me what it is in windows or BIOS so I'm guessing I'll need to open the pc up to look for model number 

 

I think I do the TDP for CPU and GPU but some say it's not nessecarily accurate so what do I base it on?

 

Once I have this info I can start adding in new parts and figure out what PSU I need

Any questions please ask thank you.

Its hard to do so, since depending on the actual workload, it can vary dramatically. Example being a 7800x3D will draw ~40-45W under gaming load which is different than its peak draw at ~120W.

 

GPUs will utilize their full TDP as long as there's not another limitation somewhere else, like if its being held back by an older/slower CPU.

 

For a mid to high end build, use a software like HWinfo64, take the TDP from the CPU+GPU and multiply it by 1.2, and you'll be pretty close. The multiplier is to compensate for losses in the PSU and other components that draw power like the RAM. Its not a scientific value, just an approximation based on my experience. At the lower end, its probably a higher multiplier, like up to 1.5.

[Mark Kaine]

4 minutes ago, Agall said:

Its hard to do so

its incredibly easy actually, IF you inform yourself about the actual TDP of your components properly its just a matter of adding them up and add like 100w (cause you'll barely get these numbers for mobos, hard-drives, etc) 

 

My PC comes to around 500w that way and max power consumption has been 507w (measured with my Corsair RMI) when running Prime95 and Superposition *at the same time*...

 

 

[Agall]

5 minutes ago, Mark Kaine said:

its incredibly easy actually, IF you inform yourself about the actual TDP of your components properly its just a matter of adding them up and add like 100w

I stay away from the raw "+X watts" because it doesn't translate across the whole spectrum. No matter, you're factoring in a multiplier due to losses in the PSU, at least 1.1, so simply dialing that up to 1.2 or 1.3 should sufficiently compensate.

 

+100W in a system with an R5 7500F and GT 1030 simply won't translate, or even going as low as a Steam Deck. That's where you'd be taking the SoC power draw and multiplying it by a factor of 1.1 or 1.2 to compensate for losses in the power supply (if going off the wall), maybe even higher since the fans will draw a disproportionately higher % compared to a full desktop.

 

The experience I have is spending a lot of time staring at my APC UPS's wattage draw that it shows on the front panel, noting about 50W steady state from my networking equipment that's also using it. My draw being significantly less now with the Ally X compared to my previous setup by about 300W.

[Mark Kaine]

24 minutes ago, Agall said:

noting about 50W steady state from my networking equipment

im talking purely about pc power draw since question is about psu.

 

 

i agree the "+100w" for mobo and connected drives/fans/etc isn't accurate but in most cases should be accurate enough... i built several systems last couple of years and that always seemed to be true... (the mobo alone draws like 30-50w i guess so that checks out depending on how many things are connected)

 

27 minutes ago, Agall said:

due to losses in the PSU

no need for that, my psu shows me this, but generally should be negligible? (give or take 20w or so)

 

[mariushm]

The wattage advertised on the label is what can be supplied to the components connected to the power supply. Conversion losses are not included in that number.

 

For example, if power supply advertises 600 watts on 12v, you can connect components that consume in total 600 watts, and the power supply may take 650 watts from the wall to produce these 600 watts - the 50 watts would be lost in transformer, mosfets diodes as heat and heat gets ejected out by the fan.

 

Modern gold efficiency power supplies will be 90% efficient or better... ex if you components consume 500w, you could say those 500w are at least 90% of the total energy consumed by the psu from the wall.

 

 

 

 

[Agall]

22 minutes ago, Mark Kaine said:

im talking purely about pc power draw since question is about psu.

 

 

i agree the "+100w" for mobo and connected drives/fans/etc isn't accurate but in most cases should be accurate enough... i built several systems last couple of years and that always seemed to be true... (the mobo alone draws like 30-50w i guess so that checks out depending on how many things are connected)

 

no need for that, my psu shows me this, but generally should be negligible? (give or take 20w or so)

 

 

PSUs aren't 100% efficient, so considering a 700W power draw from the wall, your PSU is taking about 70W of that at a 90% efficiency.

 

That's something you could measure with a watt meter and cross compare it to the wattage reported by your PSU, since I imagine that doesn't include its actual power draw. The delta between those values would be the approximate loss in the PSU's conversion.

[wONKEyeYEs]

2 hours ago, IR76 said:

I'm figuring out what my wattage max consumption is on my pc for all my components and want to know what's the best way?

 

The ram doesnt tell me what it is in windows or BIOS so I'm guessing I'll need to open the pc up to look for model number 

As @PDifolco said, PCPartpicker is pretty accurate for a close estimate.

Speccy is a free prog that will tell you about most of your pieces parts.

https://www.ccleaner.com/speccy

[Mark Kaine]

1 hour ago, Agall said:

PSUs aren't 100% efficient, so considering a 700W power draw from the wall, your PSU is taking about 70W of that at a 90% efficiency.

 

That's something you could measure with a watt meter and cross compare it to the wattage reported by your PSU, since I imagine that doesn't include its actual power draw. The delta between those values would be the approximate loss in the PSU's conversion.

look at it again it tells you exactly what the efficiency is...

 

its actually more accurate than a "watt meter" because it's basically built into the PSU.

 

Also irrelevant again since we only want to know max power draw and not efficiency,  its as easy as adding components max tdp up, as said. 

[Mark Kaine]

3 hours ago, IR76 said:

I'm figuring out what my wattage max consumption is on my pc for all my components and want to know what's the best way?

 

The ram doesnt tell me what it is in windows or BIOS so I'm guessing I'll need to open the pc up to look for model number 

 

I think I do the TDP for CPU and GPU but some say it's not nessecarily accurate so what do I base it on?

 

Once I have this info I can start adding in new parts and figure out what PSU I need

Any questions please ask thank you.

As long you don't know what components you're using this is impossible to say, but yes then its as easy as adding these things and give a margin of error of about +100w.

 

not too complicated. 

[Agall]

2 hours ago, Mark Kaine said:

 

3 minutes ago, Mark Kaine said:

look at it again it tells you exactly what the efficiency is...

 

its actually more accurate than a "watt meter" because it's basically built into the PSU.

 

Also irrelevant again since we only want to know max power draw and not efficiency,  its as easy as adding components max tdp up, as said. 

 

I would recommend taking this screenshot while under a gaming load, not while at idle. That's going to affect the power supply's power consumption, because that's how %efficiency works.

[Mark Kaine]

6 minutes ago, Agall said:

 

 

I would recommend taking this screenshot while under a gaming load, not while at idle. That's going to affect the power supply's power consumption, because that's how %efficiency works.

 

 

2 hours ago, Mark Kaine said:

My PC comes to around 500w that way and max power consumption has been 507w (measured with my Corsair RMI) when running Prime95 and Superposition *at the same time*...

 

[Agall]

16 minutes ago, Mark Kaine said:

My PC comes to around 500w that way and max power consumption has been 507w (measured with my Corsair RMI) when running Prime95 and Superposition *at the same time*...

So no picture like the one you uploaded before?

 

 

(500/507)*100 = 98.6% efficiency.

 

 

 

https://www.edn.com/efficiency-calculations-for-power-converters/#google_vignette

 

TLDR: Power delivery/conversion isn't 100% efficient, which includes the VRM. Its going to be based on the actual wattage going through the components, not an arbitrary singular value. Where I find it easier to approximate based on a multiplier. VRM should be more efficient than AC-DC conversion in a PSU, but its a more conservative value to base an approximation off of.

[Glenwing]

6 hours ago, Agall said:

(500/507)*100 = 98.6% efficiency.

Efficiency is output power divided by input power. Not estimated output power divided by measured output power.

[Agall]

8 hours ago, Glenwing said:

Efficiency is output power divided by input power. Not estimated output power divided by measured output power.

Yes, I agree and demonstrate that in the same post. Those values are what @Mark Kaine provided as a response to my question, so I'm using what values I was given. What I was a hoping for was an 'under load' screenshot of these metrics, but I got '500W' and '507W' instead.

 

14 hours ago, Agall said:

I would recommend taking this screenshot while under a gaming load, not while at idle. That's going to affect the power supply's power consumption, because that's how %efficiency works.

 

Still, this is detracting from OP's major question since the power supply's power consumption isn't applicable to its own output capacity. Tangential lecture about how efficiency works.

[Mark Kaine]

29 minutes ago, Agall said:

What I was a hoping for was an 'under load' screensho

i have no idea why you keep talking about efficiency,  that's not the topic and that's why I'll now stop responding to you.

 

you can pm me if you have questions about efficiency,  in general. 

[Agall]

1 minute ago, Mark Kaine said:

i have no idea why you keep talking about efficiency,  that's not the topic

I only keep talking about efficiency because I'm fighting against inaccuracies. I'll take your lack of willingness to upload a screenshot of your PSU software under a heavy load to contrast the one you took at idle as an acceptance of defeat... Otherwise, I genuinely don't understand where your disagreement comes in without just assuming you lack knowledge on electricity.

 

OP also asked about power draw overall as a reminder:

17 hours ago, IR76 said:

How do I calculate the wattage max consumption of my pc?

 

I'm figuring out what my wattage max consumption is on my pc for all my components and want to know what's the best way?

This includes PSU power consumption. That's obviously dependent on the load and efficiency of the PSU, but its not an insignificant amount, being in the hundreds of watts in extreme cases.

[starsmine]

On 8/5/2024 at 6:25 PM, Agall said:

PSUs aren't 100% efficient, so considering a 700W power draw from the wall, your PSU is taking about 70W of that at a 90% efficiency.

 

That's something you could measure with a watt meter and cross compare it to the wattage reported by your PSU, since I imagine that doesn't include its actual power draw. The delta between those values would be the approximate loss in the PSU's conversion.

This phrasing is weird. Not saying its wrong but I read it wrong the first time. 

For OP, a clearer way to say this, a PSU is rated for its maximum power delivery, not draw. a 90% efficient 700W PSU will PROVIDE 700W while taking 778W from the wall. There is also power factor and VA that gets things more messy, but the utilities pay for power factor, not the customer so as long their whole house is above a certain power factor anyways. 

 

[Glenwing]

On 8/6/2024 at 7:49 AM, Agall said:

OP also asked about power draw overall as a reminder:

This includes PSU power consumption.

No, I'm pretty sure he was just trying to find out how much output power he needs:

 

On 8/5/2024 at 1:50 PM, IR76 said:

Once I have this info I can start adding in new parts and figure out what PSU I need.