I want to learn about PC Wattage !

As title said. Ok i know the basic are medium to high end rigs usually only uses 550W to 750W of power. While you OC you will require more.

So thing is , how do you calculate how much do your PC needs without using a calculator ?

For example the FX 8120 CPU , it stats that it needs a whopping of 125W

Is that the full wattage it uses , does it use that much all the time ? How do you guys know how it works it never explains , just states 125W

http://www.amd.com/us/products/desktop/processors/amdfx/pages/amdfx-model-number-comparison.aspx

Same goes for GPU , it sates minimum of 500W but the GPU doesn't take 500W that much. Instead its only taking up 75W from the 6-Pin Connector am I right ? So how i know how much it requires actually and what if I OC it ?

http://www.sapphiretech.com/presentation/product/?cid=1&gid=3&sgid=1160&pid=1472&psn=&lid=1#

Just remember that not everything is about wattage...amperage is also a major requirement for GPUs.

As the PSU ages, it's power output gets weaker. So in general, you want to find the max power of CPU + GPU, and double that and round down (or 1.5 times and round up) to find the best PSU for your system.

As you suspected, the 500W number on the GPU is just the manufacturer's guess at how beefy a PSU you'll want. If you're doing the analysis yourself, the keyword you're looking for is "TDP" aka "Thermal Design Power" aka "Total Dissipated Power". For the card in question, it looks to be 130W.

For other components, it can be hard to find power ratings, so I usually go with some rules of thumb. Mobo may draw 50W, RAM 20W per stick, hard drives and optical drives 5-10W, and SSDs less than 5W. Case fans usually list how much current they draw, which can be multiplied by the voltage to get power (e.g. 12V * 0.75A = 9W).

Going by just the numbers usually overestimates things a fair amount in my experience. For example, the system in my sig has a calculated draw around 500W at load (taking into account the reduced power from undervolting and low-power RAM). In reality, my kill-a-watt has never registered much over 350W. Now, you don't want to run your PSU at 100% load, but there's enough fudge that getting a quality PSU rated above the total TDP should be fine.

JigPu

But if i dont own the GPU and CPU at the moment , can i find out exactly how much it needs ? So to find out a component's wattage needs is just their Amp X Volt = Wattage ?

Hmm if the Amp , most PSU i see from 450 - 550W range are around 35 - 36 AMP , for 650 - 750 , they are around 45 - 46 AMP i guess , if im not mistaken , is that good ?

Without trying or testing can you actually tell if the PSU really produces 550W if they state 550W

I saw a website saying that just take their given specs Amp X Volt = the Wattage of the PSU

For the rig i building its just over 300 W , so i think a 550W will be fine. I dont do OC too.
But i am curious if i do OC , how i would to check how much W i will need then ( again must i do it live or i can calculate even without having the PC now ? )

You have to be careful with that reasoning, though. My last PSU was 550 watts, but at a mere 18 amp rating.


For that setup, I would say that a 450-550 watt PSU with at least 35 amps on the 12 volt rail would be more than sufficient.


And as for knowing if the power rating is legit...just got for the PSUs with the highest average ratings. Corsair, for example is an extremely reputable brand, and makes high quality PSUs that will sometimes even go past their power ratings. On the other hand there is Diablotech....not so much from them.

only 18 amp seriously ? That bad !?

Well i be getting this for my build , i think its not bad

http://www.hardwaresecrets.com/article/Enermax-NAXN-82+-550-W-Power-Supply-Review/1426

I be running Sapphire HD 7850 2GB , FX 8120 , 1X 1TB WD BLUE HDD , 6 led casing fans, 2X 4GB 1333mhz DDR3 RAM , CoolerMaster TX3 EVO CPU Cooler thats all.

Even if i tend to OC my FX 8120 , think maybe i only be going up to 3.6 - 3.8 i doubt i will try touching 4.0

I think enermax is usually overpriced considering the ripple.

One thing most people miss is they buy TOO MUCH PSU, it is IMHO as bad as not buying enough. If you are into OCing and push stuff to the limit then yes a 850W for a single CPU and GPU is good.

the "power curve" for a PSU starts at about 25%, if your PC idling and is not using 25% of your PSU you are outside the efficiency range and have too much PSU. Now if your running a 3 GPU set, then that changes things of course. then again you arent worried about efficiency either

5-600W (quality PSU) will cover a decent GPU and CPU with a an SSD and a large HDD and 3-4 decent fans with a moderate OC. I ran a 2500K and a 3650 on a cheap 250W. With a theater pro 600 and a 1TB HDD. it was not happy im sure but was stable. I ran a thuban 6 core at stock and a 6850 then a 6770 (while using hte onboard 4290) 3 HDDs and a couple of low wattage fans on a 400W without trouble, it is a corsair CX series IIRC. I have a 700W OCZ $30 SLI unit in there right now Figure according to its real rating its putting out about the same lol

Fans are an important part though and can range from 16W for 4 fans to 36W or more pretty easily.

I agree sometimes people have quite a setup yet its still quite simple because i seen some scary **** lol. They buy whopping of 1K + W , GOLD certified too ! I thinking wao , seriously where do you people get your money from !

But in terms of bragging rights , its damn cool i say having a PSU over 1 K and its Gold certified =p

I can pretty much guarantee my build without OC a 550W its more than enough i guess.

But my questions still stands, what if I OC both my GPU and CPU , SLIGHTLY , will it still be enough ?

Also as i mentioned can i tell , if i do have it to test it out , just by reference. Like roughly calculation some how

Also do Fan controllers take much Wattage ? Example it reads here 1 channel maximum of 6 Wattage , meaning if 5 fans = 5 X 6 = 30 Watt?

I just go here http://www.extreme.outervision.com/psucalculator.jsp and use their calculator.

LOL ? I have to pay just to use a PSU Calculator ?!

We have the same PSU lol , currently at least =)

Gh0sT-NoVa said:

I agree sometimes people have quite a setup yet its still quite simple because i seen some scary **** lol. They buy whopping of 1K + W , GOLD certified too ! I thinking wao , seriously where do you people get your money from !

But in terms of bragging rights , its damn cool i say having a PSU over 1 K and its Gold certified =p

I can pretty much guarantee my build without OC a 550W its more than enough i guess.

But my questions still stands, what if I OC both my GPU and CPU , SLIGHTLY , will it still be enough ?

Also as i mentioned can i tell , if i do have it to test it out , just by reference. Like roughly calculation some how

Also do Fan controllers take much Wattage ? Example it reads here 1 channel maximum of 6 Wattage , meaning if 5 fans = 5 X 6 = 30 Watt?

Click to expand...

Looking at that Enermax PSU, it appears that you will have to balance your rails, as most of them run 3, 12 volt rails instead of 1. This is, however, based on other PSUs from that brand (I can't find that PSU on either Amazon or Newegg).

Gh0sT-NoVa said:

But if i dont own the GPU and CPU at the moment , can i find out exactly how much it needs ? So to find out a component's wattage needs is just their Amp X Volt = Wattage ?

Click to expand...

While all you need is the current ("amperage") and voltage to get power, its very rare to find those specs for most parts -- PC fans are probably the only component, actually. As I mentioned earlier, I'd just search for the TDP of the part you're interested in buying. For instance, putting "FX 8120 TDP" into Google will bring up numerous results putting the part at 125W. Similarly, searching for "HD7850 TDP" has most results pegging the card at 130W.

Gh0sT-NoVa said:

But my questions still stands, what if I OC both my GPU and CPU , SLIGHTLY , will it still be enough ?

Also as i mentioned can i tell , if i do have it to test it out , just by reference. Like roughly calculation some how

Click to expand...

The power drawn by a chip is proportional to the frequency you run it at, and the square of the voltage you run it at. Running the FX8120 at a 25% overclock and no additional voltage means you can expect a TDP around 125W * 1.25 = 156W. Increasing the voltage by 10% to hit that speed would increase TDP to 125W * 1.25 * 1.1^2 = 189W.

Gh0sT-NoVa said:

Also do Fan controllers take much Wattage ? Example it reads here 1 channel maximum of 6 Wattage , meaning if 5 fans = 5 X 6 = 30 Watt?

Click to expand...

Fan controllers themselves draw no power (at least ideally); they cut back on the power that would have been delivered to the fan. Like a PSU, the power rating is the maximum load they can handle before going up in smoke. As long as you don't connect fans that draw more than that much power to a single channel it shouldn't give you problems.

JigPu

JigPu said:

While all you need is the current ("amperage") and voltage to get power, its very rare to find those specs for most parts -- PC fans are probably the only component, actually. As I mentioned earlier, I'd just search for the TDP of the part you're interested in buying. For instance, putting "FX 8120 TDP" into Google will bring up numerous results putting the part at 125W. Similarly, searching for "HD7850 TDP" has most results pegging the card at 130W.


The power drawn by a chip is proportional to the frequency you run it at, and the square of the voltage you run it at. Running the FX8120 at a 25% overclock and no additional voltage means you can expect a TDP around 125W * 1.25 = 156W. Increasing the voltage by 10% to hit that speed would increase TDP to 125W * 1.25 * 1.1^2 = 189W.


Fan controllers themselves draw no power (at least ideally); they cut back on the power that would have been delivered to the fan. Like a PSU, the power rating is the maximum load they can handle before going up in smoke. As long as you don't connect fans that draw more than that much power to a single channel it shouldn't give you problems.

JigPu

Click to expand...

Ah i see you really clear things up for me lol , not to mention my English is weak sometimes its hard to even understand.

But the 2nd part , OCins the CPU , im still abit blur.

Are you saying if just basically OCing my 8120 by 20% but without touching the voltage , the Wattage requires wont goes up or not much at least.

Unless i touch the Voltage of it then it will require more Wattage ?

Because if not mistaken , I seen a guy who OC , he said something about changing the Voltage , he wasn't using FX8120 though , but he said not to go over 1.5 V i think ( Watch the vid at 4:00 and though this vid is made 2009 pretty old )


Big problem is i dont even know how to OC yet lol

So for fan controllers , basically your fan power and speed controlling be via the fan controllers i see , just plug them in and make sure as long your fan wattage consumption is not over the controller's wattage limit?

The PSU 12 V rails i think isnt it all 450 - 550 W , are only single. If double those are like over 650 and more.

I know one of the FSP Aurum Gold , had 3 12V Rails , those are high end PSU