PSU Wattage Confusing

[SpinSol]

 

Hello Guys So im building a pc and I still need a PSU only 

When I use wattage calculations I get different calculations in every site

Can you guys help me please pick a PSU  because it's very important 

My Config:

Cpu : I7-7700k

Cooler: MA610 CoolerMaster

Motherboard : Msi z270 gaming pro carbon

Gpu: Asus cerberus 1050 ti

Storage : 1 ssd and 1 hdd

Ram : 8 GB DDR4

Case : coolermaster h500p

And I'll be using a 24' monitor 

 

Thanks in advance

[Lennart van de Merwe]

3 minutes ago, SpinSol said:

 

Hello Guys So im building a pc and I still need a PSU only 

When I use wattage calculations I get different calculations in every site

Can you guys help me please pick a PSU  because it's very important 

My Config:

Cpu : I7-7700k

Cooler: MA610 CoolerMaster

Motherboard : Msi z270 gaming pro carbon

Gpu: Asus cerberus 1050 ti

Storage : 1 ssd and 1 hdd

Ram : 8 GB DDR4

Case : coolermaster h500p

And I'll be using a 24' monitor 

 

Thanks in advance

I know this isn't your question, but 7700K + 1050ti? Also I'd say for a psu maybe about 500 watts. I know it's overkill, but it'll give you room to upgrade the GPU in the future (something you'll want  to do).

[Jurrunio]

450w will do at this point, though better 550w for future GPU upgrades.

[Stefan Payne]

10 minutes ago, SpinSol said:

 

Hello Guys So im building a pc and I still need a PSU only 

When I use wattage calculations I get different calculations in every site

Can you guys help me please pick a PSU  because it's very important 

My Config:

Cpu : I7-7700k

Cooler: MA610 CoolerMaster

Motherboard : Msi z270 gaming pro carbon

Gpu: Asus cerberus 1050 ti

Storage : 1 ssd and 1 hdd

Ram : 8 GB DDR4

Case : coolermaster h500p

And I'll be using a 24' monitor 

 

Thanks in advance

For your information:
https://www.heise.de/ct/artikel/Exclusive-Spectre-NG-Multiple-new-Intel-CPU-flaws-revealed-several-serious-4040648.html

From what I know the NDA is lifted on monday. 

As for the configuration, it doesn't make much sense.

 

The i7-7700k is old and if you can't get it for 100€ or so its not worth it.

And the Graphics card is a bit on the small side.

 

As for the PSU:

What's available? Where are you from?

The usual recommendations:
Bitfenix Formula 450W, Cougar GX-F550W.

[Canada EH]

the more wattage the better, 550 seems to be the sweet spot as the price difference aint much at all

[AskTJ]

1050ti seems a little weak for the 7700k. Look into a 1060 6GB or 1070.

[SpinSol]

Thank you guys for your help

About the gpu : in my country graphics cards are very expensive compared to other countries so I should save uo before upgrading the gpu to a good one

[Canada EH]

1 minute ago, SpinSol said:

in my country

which is what country?

[Stefan Payne]

19 minutes ago, Canada EH said:

the more wattage the better

Naa, a 1500W PSU doesn't give you any advantage over a 450W, when you don't need the extra 1050W.

Wattage only is useful when you need it.

If you don't need the wattage, its the least important feature of a PSU.

[Canada EH]

yeah but why buy the minimum amount, theres no reason for that, just bump it up a bit

[SpinSol]

4 minutes ago, Canada EH said:

which is what country?

Morocco

[Canada EH]

1 minute ago, SpinSol said:

Morocco

Nice, shoulda went on my round the world tour

 

import tax is nasty

your just across the river from europe

[TechyBen]

You need a PSU rated for what you use, and a little above that. As efficiency curves exist. a 1500w PSU running a 250w system might use more electric than a 350w PSU running a 250w system.

 

You want 80-90% use, unless you plan on upgrading (as of cause, you'll need extra for a bigger CPU/GPU!).

[Rexper]

44 minutes ago, Canada EH said:

yeah but why buy the minimum amount, theres no reason for that, just bump it up a bit

Because that's all you need and you get no benefits at all from a higher wattage power supply? You only lose money and possibly end up with a noisier PSU.

 

19 minutes ago, TechyBen said:

You need a PSU rated for what you use, and a little above that. As efficiency curves exist.

Don't worry about efficiency curves. When you factor in the efficiency of every load the computer will be in (eg. idle, gaming) the power saved on a 550w compared to an 850w PSU, assuming they are from the same series and platform, are negligible.

 

If you want efficiency, choose a PSU that is overall more efficient. Don't waste your time messing around with wattage capacity.

 

For OP's system, 450w is more than enough. If they plan to upgrade to a top tier graphics card like a GTX 1080ti  550w will be suitable.

[bowrilla]

Most of the time your system won't be under 100% load. So even if you configured your system on the sweet spot (~80–90% use of your PSU's power rating) most of the time you'll be way (!) below that and there goes your tiny efficiency advantage. A system running Windows and a browser will rarely exceed 50–100W, most likely less. Even when gaming most of the time your CPU won't be pushed to its max. It's your GPU that's working the most. So the efficiency curve isn't all that interesting, the efficiency rating is of more interest because a higher efficiency rating means an overwhole higher efficiency. Still – your power savings will be marginal.

There's another curve in the specs of your PSU though that is of more interest: fan curve. Up to a certain level most PSUs run fanless and therefore silently. The higher your PSU is rated for the higher that threshold is set (usually – you have to compare model-wise, different models have different thresholds). 

So let's assume your system has a total power consumption under max load of 350W (reasonable considering a 7700k even with a better suiting gpu). You could easily go with a 450W psu and have some headroom though that PSU's fan will be spinning most of the time unless you're idling. Or go for a 600W model and have an overall quieter PSU since at the same loads it will be quieter (depending on models though, some models are just noisier by default).

If noise isn't a concern just take the estimated max power consumption of your system, add another 100–150W, look for a decent model (see PSU Tier List) and you're absolutely fine.

[Stefan Payne]

52 minutes ago, bowrilla said:

You could easily go with a 450W psu and have some headroom though that PSU's fan will be spinning most of the time unless you're idling. Or go for a 600W model and have an overall quieter PSU since at the same loads it will be quieter

No, because 450 and 650W usually have the same Plattform, the same heatsinks.

the relative load (in per cent) is irrelevant, the absolute load (in Watt) is relevant.

 

So with about the same efficiency, the same load and the same heatsinks, both have to be equally loud.

But because a 650W GOld unit with 90% Efficiency at 100% load has to dissipate about 72W, while the 450W only has to dissipate 50W, you can get away with a lower RPM fan because the max. loss in the PSU is smaller.

 

 

So for the 650W to be quieter, we have to talk about two different PSU - wich is never the case at 650W to my knowledge. If the plattform is changed, it either happens at 750W (for example Corsair RMx/RMi) or even 850W (for example Cooler Master V-Series, be quiet Dark Power Pro).

And sometimes even more than 850W...

[bowrilla]

1 hour ago, Stefan Payne said:

No, because 450 and 650W usually have the same Plattform, the same heatsinks.

the relative load (in per cent) is irrelevant, the absolute load (in Watt) is relevant.

 

So with about the same efficiency, the same load and the same heatsinks, both have to be equally loud.

But because a 650W GOld unit with 90% Efficiency at 100% load has to dissipate about 72W, while the 450W only has to dissipate 50W, you can get away with a lower RPM fan because the max. loss in the PSU is smaller.

It depends on the model. You don't need to change the platform in order to use beefier heatsinks. Generally speaking: if it's rated higher it uses most likely bigger heatsinks and can therefore run quieter. Of course, you need to consider your specific model.

Your comparison seems to be a bit confusing though. First you said that the absolute load is relevant (which I agree with) and then you're comparing 100% loads. 350W on a 450W PSU is ~78% load while on a 600W PSU it's ~58% load. The smaller PSU will most likely ramp up the fans to max while the bigger one won't. If it was built entirely the same with the same heatsinks and all then there are only two options: the smaller one is just rebranded and is in fact a 600W PSU or the 600W PSU isn't really built to deliver 650W. I'm not denying that there are some manufacturers who just rev up the fans. But that's not the general case in my experience. Maybe I was just lucky with my PSUs or I only chose the better ones.

I neither have time nor money to examine dozens of PSUs. I have a look at fan curves and choose my model accordingly. If you did the research and tested several models or can point me to an article that did that I'd be happy to learn something new. Not trying to be arrogant here, I'm actually interested in results that prove your point since it doesn't correlate with my experiences from when I did my "research" on finding a proper new PSU.

[Stefan Payne]

7 hours ago, bowrilla said:

It depends on the model.

Yes, I said as much. 

But normally the 650W is not any quieter, that's false.

 

7 hours ago, bowrilla said:

You don't need to change the platform in order to use beefier heatsinks.

Name an example!!

 

For example, 430W:

https://www.hardwareluxx.de/community/f238/xilence-performance-430w-1144105.html

730W:

https://www.hardwareluxx.de/community/f238/userreview-xilence-performance-730w-stefan-payne-1154551.html

 

300W Difference, both have the same Heatsink. And that's the norm, not exception.

 

7 hours ago, bowrilla said:

Generally speaking: if it's rated higher it uses most likely bigger heatsinks and can therefore run quieter. Of course, you need to consider your specific model.

Generally speaking, you are wrong and all they do is put in a higher RPM fan.

And we are back to name examples where that is the case!!

The only ones I can recall is when they change Plattforms.

 

Examples where it is NOT the case:
be quiet Straight Power 7, 8, 9, 10

Pure Power 10

Bitfenix Formula, Whisper M

Cougar GX-F
Cougar GX-S

Cougar GX V3

 

And many many more...

 

7 hours ago, bowrilla said:

Your comparison seems to be a bit confusing though. First you said that the absolute load is relevant (which I agree with) and then you're comparing 100% loads. 350W on a 450W PSU is ~78% load while on a 600W PSU it's ~58% load. The smaller PSU will most likely ramp up the fans to max while the bigger one won't.

That violates the laws of thermodynamics.

Or are you saying that the 450W stays cooler than the 600W wich gets hotter??

 

Because with the same Heatsinks on the same Plattform, what you are saying right now is impossible.

 

Just look at this:

https://www.hartware.de/2012/11/27/be-quiet-dark-power-pro-10-650w/8/

 

I've seen fan RPM diagramm of another (cheapish) series, where the even numbered have 200rpm more than the odd numbered ones.

~650W is far louder than ~550W.

 

7 hours ago, bowrilla said:

If it was built entirely the same with the same heatsinks and all then there are only two options: the smaller one is just rebranded and is in fact a 600W PSU or the 600W PSU isn't really built to deliver 650W. I'm not denying that there are some manufacturers who just rev up the fans. But that's not the general case in my experience. Maybe I was just lucky with my PSUs or I only chose the better ones.

Or they just use the same Heatsinks while they replace the FETs, Transformer, (big) Coils.

And they use a higher RPM fan in the 600W PSU!

 

Here some facts:

650W, 615rpm starting:
https://www.tomshardware.com/reviews/evga-supernova-650-p2-power-supply,4364-4.html

 

850W, 920rpm starting:

https://www.tomshardware.com/reviews/evga-supernova-850-p2-power-supply,4454-4.html

 

Both use the same Plattform, the stronge one uses just a higher RPM fan!

The 650W has a B1402512M with 0,3A (1200RPM or so), the 850W has a B1402512HH with 0,5A and 1800rpm or so.

 

7 hours ago, bowrilla said:

I neither have time nor money to examine dozens of PSUs. I have a look at fan curves and choose my model accordingly. If you did the research and tested several models or can point me to an article that did that I'd be happy to learn something new. Not trying to be arrogant here, I'm actually interested in results that prove your point since it doesn't correlate with my experiences from when I did my "research" on finding a proper new PSU.

You claimed something, you have to prove your claim!

 

Just think for a second, how should a 450W with the same heatsinks as an 850W (Bitfenix Whisper M) be any louder under any circumstances, when both are loaded about the same, efficiency is about the same and about the same heat is produced inside the PSU. 

How can that work?!

 

The only logical explanation is that the 850W ones runs way hotter than the 450W one wich reduces the life expectancy.

 

You just can look at Reviews from Tomshardware and Techpowerup, both are done by the same guy...

[Canada EH]

So you buy a minimum psu, and later decide that the newest gpu's require more power, so by not bumping up the wattage a bit, you now require to buy a new psu.

[Stefan Payne]

3 hours ago, Canada EH said:

So you buy a minimum psu, and later decide that the newest gpu's require more power, so by not bumping up the wattage a bit, you now require to buy a new psu.

Hasn't happened in 10 Years...

 

And even my Radeon HD7970GHz Edition works fine with a good 400W unit and an i7-3930K, without OC of course.

[bowrilla]

12 hours ago, Stefan Payne said:

[…]

Pal, no need to be aggressive or hostile. As I said: I was speaking from my personal experience but I'm happy to learn something new. 

[Stefan Payne]

10 hours ago, bowrilla said:

Pal, no need to be aggressive or hostile.

1. just your imagination.

2. Imagine how you would react if someone said something you know is completely false, you have debunked a couple of dozen times...

 

10 hours ago, bowrilla said:

As I said: I was speaking from my personal experience

you never mentioned what units you were talking about...

 

10 hours ago, bowrilla said:

but I'm happy to learn something new. 

Great, now you learned something new and can bring the new knowledge to other places where I'm not

[SpinSol]

Guys thanks for your replies Im thinking of getting the Corsair rm 650 is it good for my build ?

 

[SpinSol]

On 5/5/2018 at 11:01 AM, Canada EH said:

Nice, shoulda went on my round the world tour

 

import tax is nasty

your just across the river from europe

Ikr like sometimes they add more than 150$ for products

[breixobaloca]

RM650 or RM650x?