How do watts work?

[QuantumBit]

Hello!

 

So I'm building a gaming PC soon and it obviously needs power, which I already have sorted out. I understand the PC takes watts, but how often? When the power consumption is something like 280 W, does that mean 280 W every second? minute? hour? day?

 

Thanks!

[TheRandomness]

280W constantly. 

[Megah3rtz]

Constantly. 

[QuantumBit]

1 minute ago, Megah3rtz said:

Constantly. 

Oh.. Is there any sort of way I can calculate the cost of it?

[Megah3rtz]

Just now, QuantumBit said:

Oh.. Is there any sort of way I can calculate the cost of it?

You mean calculate the amount of watts your power supply needs to give? or how much you're paying for your electricity bill? 

[TheRandomness]

2 minutes ago, QuantumBit said:

Oh.. Is there any sort of way I can calculate the cost of it?

Less than $10 a year. That's about how much it'd affect your bill. 

[colonel_mortis]

280W means 280 joules of energy per second. Electricity is often sold in kilowatt hours, kWh, which is the amount of energy used by a 1000W device in an hour (=3,600,000 joules), so if you look up the price per kWh for electricity for you, then multiply it by 280/1000, that will give the cost per hour of running it.

[manikyath]

should also note that modern computers will "slow themselves down" when they arent under high load, which greatly reduces power consumption, my server for example is rocking an i7 4770, two hard drives, SSD, and a GT640, and it generally doesnt go over 40 watts because it's usually idle. (whereas a full load scenario would be more along the range of 120~ watts)

[XenosTech]

4 minutes ago, manikyath said:

should also note that modern computers will "slow themselves down" when they arent under high load, which greatly reduces power consumption, my server for example is rocking an i7 4770, two hard drives, SSD, and a GT640, and it generally doesnt go over 40 watts because it's usually idle. (whereas a full load scenario would be more along the range of 120~ watts)

Sam can be said for my current rig... doing stuff like watching yt vids and browsing the web my power draw is 60-85 watts and when I put my gpu under full load that rockets up to 258 watts (I use my UPS to see what my power draw is.)

[Logue]

So, basically, what you need to know is this:

 

1) Your power supply is supposed to give as much wattage to your whole system at every single instant (fraction of a second).

2) Number 1 won't happen if: 1) your rig is drawing more power than your power supply can deliver; 2) your power supply is bad.

3) So, first thing: DON'T CHEAP OUT ON YOUR POWER SUPPLY. Look for reputable brands (EVGA, Corsair, Seasonic are the ones I'd recommend, but you can search others). Also, it's recommended that you buy a power supply that has an 80+ rating of some sort. This rating basically means your power supply has an efficiency of at least 80% while under load (the better the standard, the more efficient the PSU, so in order of efficiency: 80+ Titanium, Platinum, Gold, Silver, Bronze and White).

4) Also, you can you use online calculators (just Google 'EVGA Power Calculator" or something). That usually gives you two numbers: 1) how much power your system is probably going to draw from the wall (an average of, at least) and 2) a recommended wattage for a power supply (depending, obviously, on the items you have in your PC). You should always consider a PSU that's above the wattage your PC is going to draw (so, let's say your PC draws 280W, you should consider a PSU of 500W or 550W). Why, you might ask? Well, it's all about efficiency again: your PSU is at it's most efficient when it's being used at around 50% load. So, aside from the common knowledge that's always good to have some room to breathe in terms of wattage (you shouldn't try to get a PSU that's 300W if your PC is drawing 280W, because then your PSU will be almost at all times at 90%-100% load, which is bad for efficiency - meaning your PSU will draw more power and heat up more.

 

Hopefully that can get you started. Check LTT videos about PSUs. I recommend the following: Picking the right PSU - TechQuickie and Why you don't need so High Wattage PSUs (probably, anyway).

 

ADDED: also, check out some forum posts in the PSU section such as How many watts do I need, More information on 80+ ratings PSU Tier List

Edited December 5, 2016 by Logue
Added links for LTT Forum topics

[JefferyD90]

1 hour ago, QuantumBit said:

Hello!

 

So I'm building a gaming PC soon and it obviously needs power, which I already have sorted out. I understand the PC takes watts, but how often? When the power consumption is something like 280 W, does that mean 280 W every second? minute? hour? day?

 

Thanks!

Watts = AMPS x Voltage @ 1 Ohms...  Its a continuous thing,

[juretrn]

In physics, power is the rate of doing work. It is the amount of energy consumed per unit time. (wikipedia)

Watt is defined as Joule/second.

Multiply power by amount of seconds it has been applied and you get energy (in Joules; electricity is usually measured in watt hours.)

[Mira Yurizaki]

8 hours ago, QuantumBit said:

Hello!

 

So I'm building a gaming PC soon and it obviously needs power, which I already have sorted out. I understand the PC takes watts, but how often? When the power consumption is something like 280 W, does that mean 280 W every second? minute? hour? day?

 

Thanks!

For metering purposes, power consumption is measured in kilowatt hours. A kilowatt hour is the power consumption of one kilowatt in an hour. So if the computer were drawing 280W constantly, it would be 0.28 kWH.

 

So if you were to use a meter like a Kill-A-Watt, it's really how many watts per hour the device is using.

[Unhelpful]

8 hours ago, colonel_mortis said:

280W means 280 joules of energy per second. Electricity is often sold in kilowatt hours, kWh, which is the amount of energy used by a 1000W device in an hour (=3,600,000 joules), so if you look up the price per kWh for electricity for you, then multiply it by 280/1000, that will give the cost per hour of running it.

Unless we're talking wholesale power trading... Then it's typically MWh and GWh  

[kelvindeschutter]

8 hours ago, QuantumBit said:

Hello!

 

So I'm building a gaming PC soon and it obviously needs power, which I already have sorted out. I understand the PC takes watts, but how often? When the power consumption is something like 280 W, does that mean 280 W every second? minute? hour? day?

 

Thanks!

those 280 watts is being pulled constantly (this will be amused for this sum) but there is a easy way to see how much power the pc will use every hour.

E = 280 W = 0,28 KW (Kilowatts is what normally is used in the calculation to calculate you electricity bill)

T = 1 hour (can also be more or less than 1 hour)

E*T=0,28 KW*1 hour = 0,28KWH (Kilo watt hour) <= the amount of energy being used by our pc in an hour (this method can also be used on any other electric device as long as you convered it to KW. 1 KW = 1000 W)

note: if you want to know how much it will cost just do KWH * energy cost per KWH

[DexterSmythe]

8 hours ago, QuantumBit said:

Hello!

 

So I'm building a gaming PC soon and it obviously needs power, which I already have sorted out. I understand the PC takes watts, but how often? When the power consumption is something like 280 W, does that mean 280 W every second? minute? hour? day?

 

Thanks!

280 watts will be your max load, not your constant load. Max load will be achieved in things like games, rendering and 3D Design. You will have a much lower power consumption at idle which is things like web browsing, email, word processing, etc.

[Sauron]

8 hours ago, QuantumBit said:

Hello!

 

So I'm building a gaming PC soon and it obviously needs power, which I already have sorted out. I understand the PC takes watts, but how often? When the power consumption is something like 280 W, does that mean 280 W every second? minute? hour? day?

 

Thanks!

Watts are a measure of energy over time. 280W mean 280 Joules per second.

[QuantumBit]

9 hours ago, colonel_mortis said:

280W means 280 joules of energy per second. Electricity is often sold in kilowatt hours, kWh, which is the amount of energy used by a 1000W device in an hour (=3,600,000 joules), so if you look up the price per kWh for electricity for you, then multiply it by 280/1000, that will give the cost per hour of running it.

Thank you!

[QuantumBit]

Thanks to everyone all the replied were super helpful, sorry I cannot put multiple "solutions" up at one time