PSU Calculation

[enes3626]

When i try to calculate my PC's power consumption with OuterVision Power Supply Calculator it shows a value of 230 Watts.

But when i calculate it by hand i get this:

 

• CPU(E8400):60W

• GPU(R7 240): 30W

• RAM(2*2GB):10W

• HDD(Sata 7200):10W

• Motherboard: 30W

• 4*USB2.0 : 10W

In total i get 150W.

 

Which one is correct? Why there is so much diffrence between them? Btw i need to calculate it because i have a 300W, 80+ power supply. And i want to upgrade.

[GoldenLag]

5 minutes ago, enes3626 said:

Btw i need to calculate it because i have a 300W, 80+ power supply

what 300w PSU?

 

and you dont really want to use that PSU for anything unless its a Delta

[enes3626]

I didn't buy the system yet. It is a OEM Computer(Fujitsu) with an 300w power supply. It says it is a 80+ power supply. I wan to upgrade the cpu can i do that?

[GoldenLag]

19 minutes ago, enes3626 said:

I didn't buy the system yet. It is a OEM Computer(Fujitsu) with an 300w power supply. It says it is a 80+ power supply. I wan to upgrade the cpu can i do that?

yes you would want to swap the PSU for anything

[enes3626]

Can you tell me why the my calculation and the outerviseon calculation is so diffrent?

[GoldenLag]

Just now, enes3626 said:

Can you tell me why the my calculation and the outerviseon calculation is so diffrent?

because yours is based on TDP that is wrong. and outervision is a PSU calculator that fundamentally overestimate

[enes3626]

One last question: where can i find the real power usage of the components?

[GoldenLag]

1 minute ago, enes3626 said:

One last question: where can i find the real power usage of the components?

you dont, the closest you get is finding reviews with peak figures. 

 

otherwise you estimate. 

 

or just ask on forums. general rule is a good 550 watt PSU is enough. 

 

just get a cx550. 

[goto10]

most manufacturers never give exact numbers, that is why you see reviewers trying to measure amperages and voltages with lots of equipment

 

none gives exact numbers really, they promise tdp that sometimes is wrong or optimistic

 

what you can measure easily is total power consumption, buy a killawatt

 

remember that if you buy a too small psu it will work at the limit under load, so it will generate heat and makes noise thanks to the fan it has

 

a fujitsu prebuild pc might use a custom psu that you might not be able to change for a normal psu sold in stores

[enes3626]

Ok thanks a lot

[enes3626]

9 minutes ago, goto10 said:

most manufacturers never give exact numbers, that is why you see reviewers trying to measure amperages and voltages with lots of equipment

 

none gives exact numbers really, they promise tdp that sometimes is wrong or optimistic

 

what you can measure easily is total power consumption, buy a killawatt

 

remember that if you buy a too small psu it will work at the limit under load, so it will generate heat and makes noise thanks to the fan it has

 

a fujitsu prebuild pc might use a custom psu that you might not be able to change for a normal psu sold in stores

You're right. PSU has a diffrent design. You said thoose TDP values are optimistic. But even if i double them it looks like there is a little bit space lefts for upgrade. Current cpu is 60 Watts and i want to put a 80 Watt cpu to the system. Can i do it?

[Fasauceome]

19 minutes ago, enes3626 said:

One last question: where can i find the real power usage of the components?

If you want, you can take the route I did and buy a power meter online for like $15. You just plug it into an outlet and it tells you all the power being pulled by whatever devices are plugged in.

[GoldenLag]

3 minutes ago, enes3626 said:

Can i do it?

would avoid it

[enes3626]

Just now, fasauceome said:

If you want, you can take the route I did and buy a power meter online for like $15. You just plug it into an outlet and it tells you all the power being pulled by whatever devices are plugged in.

I'll take a look thanks.

[goto10]

is not if you can, is about if you should

 

those oem come designed to have weak parts, that is why they come in smaller capacities

 

the cpu under load might use more than 80

 

psu will feel the load when you add a gpu, you will hear that psu fully loaded, if it overloads it will overheat and might shut down

 

your gpu is really weak, if you put something more strong, be sure to replace that psu

 

go ahead but keep in mind that the psu is for light office load, well, with that gpu will not be a gaming pc either

 

i expect your pc to use around 170 watts, so psu should be fine, once you replace gpu, you will need another psu probably

 

[KEIN NEIN]

54 minutes ago, enes3626 said:

When i try to calculate my PC's power consumption with OuterVision Power Supply Calculator it shows a value of 230 Watts.

But when i calculate it by hand i get this:

 

• CPU(E8400):60W

• GPU(R7 240): 30W

• RAM(2*2GB):10W

• HDD(Sata 7200):10W

• Motherboard: 30W

• 4*USB2.0 : 10W

In total i get 150W.

 

Which one is correct? Why there is so much diffrence between them? Btw i need to calculate it because i have a 300W, 80+ power supply. And i want to upgrade.

Don't waste time and affort doing that much time

 

firstly you probably took TDPs, not power consumption figures and TDP DOES NOT EQUAL POWER DRAW

 

You can do this instead:

 

Look for your CPU's power consumption but NOTICE the test results MUST be whole-system power consumption numbers. In other words power consumption of a system with an E8400 (go with faster CPU from the same microarchitecture if you don't find the exact same one)

 

Websites like gamers nexus or tomshardware for example measure CPU power draw from the EPS connectors so they are good for efficiency comparisons but WON'T HELP YOU FIGURE OUT HOW MUCH YOU NEED

 

Try other reliable sources that don't use this method, such as anandtech, techpowerup, etc

 

Quote

Forget about wasting time with fan, SSD, HDD power draw numbers as they use a very small amount of power and if you use the method explained above you take into account all of those anyway.

 

Then loofk for reliable GPU power consumption tests, this time it is GPU only power draw, not GPU with the whole system. (Because the rest of the system is ALREADY included above) tomshardware, gamers nexus, or whatever

 

[KEIN NEIN]

1 hour ago, enes3626 said:

 

In total i get 150W.

 

Which one is correct? Why there is so much diffrence between them? Btw i need to calculate it because i have a 300W, 80+ power supply. And i want to upgrade.

E8400 OC'ed to 4 GHz (do pay attention to wether or not the tests were performed with an OC'ed CPU)@ tomshardware = 131.1W

 

https://www.tomshardware.com/reviews/ivy-bridge-wolfdale-yorkfield-comparison,3487-19.html

 

I forgot to mention use maximum load values (blender, prime 95 with AVX) because unless you only use it for web browsing you want to make sure your PSU doesn't shut off at the middle of an intensive content creation load.

 

GPU was a bit trickier as I had to substract the idle system power consumption (in that time tomshardware couldn't measure the power drawn by the GPU through the PCIe cables)

 

Total system power of an R7 240 MINUS idle system power = 122W - 57W = 65W

 

https://www.tomshardware.com/reviews/radeon-r7-240-and-250,3717-9.html

 

We add up the numbers and we get 196.1W

 

Needless to say there are more variables than just what CPU and GPU you use (the model and specific parts that the system houses) but again that is way too much hassle and 196.1W IS A SAFE NUMBER ANYWAY (unless you max out drives, SSDs deliberately), round it up to 200W, if you choose a 200W PSU (should you find one) it is nearly impossible to hit that number (At the time they measured power from the wall, considering psus are 80-90% efficient the actual power capability required for the PSU to drive all of that is less)

 

We are considering max CPU power draw + high CPU power draw (prime 95 on the CPU) so yeah it is a safe number

Quote

 

TLDR: HIGHEST TOTAL SYSTEM POWER DRAW OF PC WITH THE CPU (OR THE HIGHEST YOU CAN FIND) + HIGHEST POSSIBLE POWER DRAW OF GPU ALONE AND YOU ARE GOOD TO GO

 

No idle power, no TDP, no nvidia minimum power requirement, no AMD minimum power requirement, no pcpartpicker calc, no PSU calculator junk (those are TDP-based either way), no blind estimates (like the people that just say I recommend 1000W bc that is what I use and works)  none of that nonsense BS

 

OR YOU COULD JUST ASK "HOW MUCH DO I NEED AND EXPERTS WILL HELP".

 

 

Nontheless, if you you want to get that know-how, this is how I "summarize" (I never explained the underlying stuff because too long and boring for us to be able to handle it)

 

[KEIN NEIN]

1 hour ago, GoldenLag said:

what 300w PSU?

 

and you dont really want to use that PSU for anything unless its a Delta

but why? There are many other OEMs that make OKeish PSUs as well. Saying "buy X brand because Y and Z brand are no good" doesn't work

 

1 hour ago, enes3626 said:

I didn't buy the system yet. It is a OEM Computer(Fujitsu) with an 300w power supply. It says it is a 80+ power supply. I wan to upgrade the cpu can i do that?

80+ is an efficiency rating, not a quality one

1 hour ago, enes3626 said:

One last question: where can i find the real power usage of the components?

You need special equipment to do so, cheap watt metters don't count. 

 

The absolute minimum you can use is a current clamp and I don't encourage you to buy one unless you are a hardware-reviewer or electrical-engineer, don't waste money on stuff you will only use once. Use simple math as shown above. IT'S FREE

 

But if you are insterested you measure how much current is going through each cable and then multiply by the voltage is cable (if you want somewhat accurate readings then you also need to measure the actual voltages on each cables)

 

Again, too much hassle and a waste of money, and it's not even that precise

 

Just have a look at what these guys use, it is neither simple nor cheap:

 

https://www.tomshardware.com/reviews/power-consumption-measurement-cpu-gpu-components-powenetics,5481.html

 

48 minutes ago, fasauceome said:

If you want, you can take the route I did and buy a power meter online for like $15. You just plug it into an outlet and it tells you all the power being pulled by whatever devices are plugged in.

Don't tell him to spend money on watt meters, he really doesn't have to.

 

They aren't that precise anyway, and then you find yourself messing up with efficiency calculations and bla bla...

 

I don't know how much a watt meter costs in whenever he lives, but I have to say buying a good 450-750W PSU (which is already overkill for what he has) is a much better advice.

[TheKDub]

1 hour ago, enes3626 said:

When i try to calculate my PC's power consumption with OuterVision Power Supply Calculator it shows a value of 230 Watts.

But when i calculate it by hand i get this:

 

• CPU(E8400):60W

• GPU(R7 240): 30W

• RAM(2*2GB):10W

• HDD(Sata 7200):10W

• Motherboard: 30W

• 4*USB2.0 : 10W

In total i get 150W.

 

Which one is correct? Why there is so much diffrence between them? Btw i need to calculate it because i have a 300W, 80+ power supply. And i want to upgrade.

If you want to leave plenty of room for future upgrades, and even have something worth taking with you if you replace your PC with a newer and more powerful build, get a 600-800W PSU. I'm a fan of EVGA's G2/G3 power supplies, though they can run a little pricy.

 

My biggest suggestion is to make sure it's not just 80+, but something like 80+ Bronze, 80+ Gold, etc... and go either modular or semi-modular. Much easier to work with than non-modular power supplies, and they look so much better.

[goto10]

people, calm down, this is a cheap oem pc with a small upgrade

 

also, stop beating the horse

 

about the killawatt, is usefull to check how much watts your pcs and any other electric appliance you have uses, if you care about power consumption and electricity costs

[KEIN NEIN]

5 minutes ago, TheKDub said:

If you want to leave plenty of room for future upgrades, and even have something worth taking with you if you replace your PC with a newer and more powerful build, get a 600-800W PSU. I'm a fan of EVGA's G2/G3 power supplies, though they can run a little pricy.

 

While not bad, EVGA G2/G3 aren't usually the best value (unless he finds a deal or something)

 

I think EVGA is overvalued as a PSU brand

6 minutes ago, TheKDub said:

My biggest suggestion is to make sure it's not just 80+, but something like 80+ Bronze, 80+ Gold, etc... and go either modular or semi-modular. Much easier to work with than non-modular power supplies, and they look so much better.

Stop generalizing

 

80+ gold is not necessarily better than 80+ bronze (even if you find more quality PSUs as you go higher in 80+ rating)

 

And non-modular PSUs are not a MUST, I do not know wether or not you implied that, but if he has a case with good cable management and knows how to route cable there is nothing wrong with non-modular PSUs.

 

I am personally all about the quality, specially with electronics, you don't want to mess up with electricity, of course because it is risky, and good PSUs are cheap nowadays.

 

To me modularity are add-ons that are not as important as people think, in my experience you can build a clean PC without using a modular PSU, and I'd trade off modular cables for better quality all day long

[goto10]

1 minute ago, KEIN NEIN said:

While not bad, EVGA G2/G3 aren't usually the best value (unless he finds a deal or something)

 

I think EVGA is overvalued as a PSU brand

Stop generalizing

 

80+ gold is not necessarily better than 80+ bronze (even if you find more quality PSUs as you go higher in 80+ rating)

 

And non-modular PSUs are not a MUST, I do not know wether or not you implied that, but if he has a case with good cable management and knows how to route cable there is nothing wrong with non-modular PSUs.

 

I am personally all about the quality, specially with electronics, you don't want to mess up with electricity, of course because it is risky, and good PSUs are cheap nowadays.

 

To me modularity are add-ons that are not as important as people think, in my experience you can build a clean PC without using a modular PSU, and I'd trade off modular cables for better quality all day long

poor horse, is dead, stop it, is horrible!

[KEIN NEIN]

1 minute ago, goto10 said:

people, calm down, this is a cheap oem pc with a small upgrade

 

also, stop beating the horse

 

about the killawatt, is usefull to check how much watts your pcs and any other electric appliance you have uses, if you care about power consumption and electricity costs

I reiterate, they ARE NOT accurate, and you should have a power meter on your electrical instalation 

 

Did I know nothing about electronics I would delegate someone to do that for me, it is faster and cheaper in the long-run.

 

[KEIN NEIN]

1 minute ago, goto10 said:

poor horse, is dead, stop it, is horrible!

I never insulted him so I do not get the point

 

could you please explain?

[goto10]

i didnt said anyone insuted anyone, the topic reachet its limit is what i wanted to express

 

op got the information, he should get a new psu but the one he has should be sort of enough

 

so complain about bronze psu, tdp calculations and other details does not help anyone, so, stop beating the dead horse, is already dead, nothing will come from it, that is all