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How many watts is your main computer's power supply?

by Marc Bennett CNET staff/forum admin / April 26, 2006 8:52 AM PDT

How many watts is your main computer's power supply? (And on what kind of system?)

100 to 150 watts
151 to 250 watts
251 to 350 watts
351 to 450 watts
451 to 550 watts
551 to 650 watts
651 to 750 watts
751+ watts (what the heck are you running?)
I have no clue

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(NT) (NT) Aspire 520W PSU in an AMD Athlon64 3700+ system.
by John.Wilkinson / April 26, 2006 9:33 AM PDT
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AMD 3700+ System
by High Sierra / April 28, 2006 3:07 AM PDT

-ASUS A8N-E MB ATX 939Nforce4 Ultra DDR PCI-E16 PCI-e4 2PCI-E1 3PCI SATA RAID GBLAN sound.
-AMD Athlon 64 3700+
-1 gig PC3200 Dual Channel.
-Thermaltake TR2 W0090 470W.
-Antec Plus1080 Tower Case,
-Seagate Barracuda 7200.7 Plus 160GB IDE ATA100 7200RPM 8 MB 8.5MS Hard drive,
-IBM Deskstar 75GXP 30GB EIDE
-SB Live Sound card,
-Sony spressa 145E CD burner
-Liteon SOHW-1633S DVD Burner

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Main Computer PSU
by Dave_H / April 27, 2006 7:06 PM PDT

Unfortunately, many of the power supplies available today do not give their rated or advertised output. Here are a couple of examples:
1) In an article I read on the web site of a UK computer enthusiast magazine, they tested 29 power supplies and some of them went up in smoke before achieving their ''rated'' output! In all but a very few cases, the ''rated'' output was really ''peak'' output, and could not be held for very long at all.
2) ExtremeTech was testing some high-end graphics setups and found that even some ''SLI Approved'' PSU's just weren't up to the task--they couldn't get through their testing without having to upgrade to one of the ''big boys'' from PC Power & Cooling.
I had what I thought was a more than adequate 480 watt PSU from Thermaltake, but after upgrading my ASUS P4C800E Deluxe mobo to a 3.4E GHZ Prescott CPU and an ATI All-In-Wonder X800XT video card I started getting random reboots. After using an online wattage calculator I determined that my system was idling around 460 watts before putting any load on it. You should have 50 watts of headroom when figuring out your final load, so that 480 watter just wasn't cutting it.
I upgraded to a PC Power & Cooling TurboCool 510 Deluxe (which will deliver 650 watts peak for an extended period) and have been very satisfied with it, but found out after I ordered that I could have gotten similar performance and quieter operation at substantiallly less cost from a Seasonic S12-500. Seasonic also has a 600 watt version (and these are steady load ratings, not peak load like the ''better known'' PSU's that are heavily advertised), and PC P&C has 850 and 1000 watt SLI/Crossfire units available (the largest in the industry right now).
I'd never heard of Seasonic before reading the article on the UK site, but it turns out they are a long-time manufacturer of mission-critical server power supplies.
I'm just a DIY enthusiast, but I do overclock and tune for performance. In the future, Seasonic and PC P&C are the only PSU companies that will get my business. I feel they are the only manufacturers out there truly delivering what is on the label (and more).

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I have a strange computer
by sgtdisturbed47 / April 27, 2006 7:31 PM PDT

I bought my computer off of Ebay for 800 bucks, is it a custom built computer, and it came with an LCD 17 inch Dell monitor. It is a 3 GHz Pentium 4 w/HT, 2 gigs of RAM, 160 gig hard drive, 256 megabyte Nvidia GeForce FX 6600 and external Creative Labs Sound Blaster Live! USB sound card. Alltogether, ot works, well, kinda ok. The problem is, it only has a 112 watt power supply. It can switch to 230 watts, but when I try to start the computer when the switch is on 212 Watts, it doesnt start. It powers on, but doesn't boot. So, since it runs with such low power supply, the graphice card doesnt seem to run very well, causing severe tearing and shearing of the graphics. Very anoying. Does anyone know how I can run my computer on 212 watts instead of the measly 112 watts? Again, it powers on, I hear the fans spin, but it doesnt boot. What can I do? Pls help.

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Don't touch that switch!!
by 53helofe / April 27, 2006 8:35 PM PDT

Please please leave that switch on the back of your power supply alone! That switch is for the input voltage. It is for use in different countries, the power supply in the UK is 230 Volts, Europe is 110V aswell as the US. Changing this switch can permanently damage your computer! If you want to know the power rate of your PSU then go into BIOS, should tell you in there, if not open up the side of your case and have a look at the sticker on the PSU.

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dajoebomb is right, do Not mess with that switch
by theandy83 / April 27, 2006 11:20 PM PDT

a couple years back i flipped that switch..
i ruined a perfectly good HP PAVILION with a p4 1.8ghz 512 RAM a 48x/24x cd burner and a 30 gig hard drive. icant really remember but i think it had aintegraeted graphics and 16mb 3d graphics.

i kept the burner and i just happened to install it in my current computer last night!
p.s. it workes!! it workes!!

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Power supply and voltage
by bigduke / April 28, 2006 12:49 AM PDT

Europe is essentialy all on 220 Volts, 50 Hz. Japan is the split country with some 110 V and some 220. Check first, rather than taking a chance with a single voltage switchable supply.

Many power supplies are automatically able to run on any reasonable voltage without switches.

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212 watts is pretty measly too
by David_J_D / April 27, 2006 8:38 PM PDT

Seems like you should be running at least 350 watts, if not 400-450. Get a new power supply is my advice.

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just between you and me there's no such thing ;)
by xcarcraft / May 18, 2006 5:10 AM PDT

but then again I think I saw an ad for a 313.3 Watt psu on ebay! Runs at 550 Volts! Wink

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You need way more power
by ms32dk / April 28, 2006 12:21 AM PDT

If you add up the power usage of each component and add 20% you are going to need at least 300W supply I would go with 350W min. Buy a new power supply.

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How do you find power consumption?
by jl54 / May 3, 2006 4:27 AM PDT

Is it listed on the actual parts or in BIOS or what? Also, there are a thousand parts in a system. What are the components that i have to take into consideration? thanks.

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by John.Wilkinson / May 3, 2006 8:50 AM PDT

To find out how many watts your PSU can put out, click here. To find out how many it consumes is a little trickier. You have to consider things such as your CPU, drives, RAM, video/sound/tuner cards, fans (or other method of cooling), etc. For a good calculator that will estimate how many watts your PC consumes, click here.

Just remember that:
* It's an estimate.
* The PSU's performance will degrade with age.
* Every time you make a hardware upgrade, you're upping the watts.

Thus, a good rule of thumb is get one that's rated 100W higher than what you think you need, that way you're prepared for what might come up.

Hope this helps,

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Thanks :)
by jl54 / May 3, 2006 4:47 PM PDT
In reply to: Calculation...

The calculator works awesome. Looks like I'm reccomended to use 350 watts. Thanks for the great link Happy

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I have a nice solution
by rjkboyle / April 28, 2006 8:41 AM PDT

Go to a local computer store, mostly anywhere that has computer supplys, and spend the $25 - $100 and get a new 400 Watt power supply, that should solve everything quite nicely.

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PSU's are cheap just go find a new one...
by ythe1300 / April 29, 2006 9:40 PM PDT

... that works in you case and with your motherboard.

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112volts not watts
by apart2long / April 30, 2006 7:17 AM PDT

most power supplys are dualvoltage 115/110/120 or 220v all plus or minus 10percent.

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Voltage, Watts, What's the difference?
by chaissos / April 30, 2006 8:50 AM PDT

OK, PSU's come in basically three varieties: 115V only, 230V only, and switchable between 115V/230V (don't get too technical here, 115V is pretty much anything between 105V and 130V, 230V is between 205V and 250V). You'll have to look closer at your PSU to discover exactly what the power output (in watts) actually is.

Now, to be clear, if you set the input voltage (the switch on the back) to 230V, and plug it into 110V, there should be no damage to anything in your box. I've done it quite a few times, during my 15 years living in Europe (220V standard), and the UK (240V standard). Some people used transformers to run their systems on 110V. I used all 240V (or 220V). The differences are electrical, and have mostly to do with power surges and what-not, so I'll not get into that too deeply. However, if you go the other way (set it to 110V and plug it into 240V), you stand the risk of blowing anything from the power supply itself (extremely likely), to any (and every) component in the box. I've done that, too. More than once, however, for me, the only thing ever damaged was the PSU itself. Normally, I just fixed them (fuses and capacitors are the first things to go).

Output power, in watts, is basically what your PSU will support in normal use. Typically, they'll accept a higher peak (only for very short periods), and will run more efficiently if there's a nice overhead (like about 100w).

So check the writing on the actual PSU itself. You may have to remove it to do that, but look for a model number. Somewhere on the little sticker there should be a max output power listed. I have two in my hands here, and the model numbers are HP-P2507FWP (it's a Dell PSU). Max output power is 250w. The other is a Fortron/Source, model FSP200-60GI, output power is 200W.

Have another look. Most likely yours is 250W or more.


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Fan speed - forgot this part...
by chaissos / April 30, 2006 8:54 AM PDT

I meant to stick it in the last post, but spaced it....

Fan speed isn't really meant to be all that fast. Newer systems will have relatively slow fans in them. The fan speed will be internally controlled by heat sensors. If the PSU is running normally, there shouldn't be that much of a breeze. If you can dry your hair back there, then there's something wrong.

The PSU fan is only meant to cool the PSU, not the entire system. You should have at least one case fan (I've got 7 fans in my systems, at least three in each server).

OK, that's it (I think)... Happy

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My pc has a mean owner!
by xcarcraft / May 18, 2006 5:02 AM PDT

wow! I'm surprised your comp has lived as long as it has! I'd be leaving that switch on the PSU alone IF I WERE YOU! I think if you have a closer look you'll find it's to adjust the VOLTAGE not WATTAGE. don't know about 212 watts but 112 and 230 VOLTS sounds about right! If you live in a country with around 112 volts power in the mains, you best leave that switch alone! IF I did what you did, I would have no psu, no mobo and proberbly no cpu and ram! some people are just born lucky I have to use other means to get though life!

From what I've seen most psu's come with a max power rating and that's it! ie 350,400,450 ect! I'd say take the cover of you pc and read what it says on the psu, but from what I've read that wouldn't be a good recomenation

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by Hal R. Hosfeld / December 27, 2006 6:04 AM PST

It's people like you who make people like me look smart!

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pc wattage
by The Clue / April 27, 2006 7:39 PM PDT

I use Intel processors in the systems that I build. I like to use power supplies with at least 450W or above. The main reason for that is the demands that are put on the pc's today. Most pc's are running a program, the DVD player, multi monitors, and sometimes games all at the same time, not to mention the power to the main board and cooling systems. This puts a high demand on the power supply and if it is under powered something might be damaged not to mention damaging the power supply itself, from over heating. I like having more power than needed that way there is always room to expand or upgrade, without having to buy another power sorce to meet the new needs of the pc. Just a thought.

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Home Built and ready for the Boneyard.
by najie / April 28, 2006 3:21 AM PDT
In reply to: pc wattage

This was my first build and on a budget. System contents: Generic case from computer fair with 4-5 1/4 front bays and 2-3 1/2 front bays, room for 4 internal hard drives (Mid-size tower) I have an Antec Tru Power 430 power supply powering: an Intel D865Perl MoBo W/P-4 3.06 proc, 2 gb (4-512 mb Kingston DDR-3200)memory, Stock CPU fan, 4 case fans (one in the top), ATI Radeon 9550 graphics card (I Know) SB Audigy2 ZS sound card, Modem card, Controller card for additional hard drive, three hard drives (160/120/80), four optical drives (1 liteOn 52X CD, 2 Plextor PX-716SA DVD Multi, 1 LiteOn 8X DVD Multi) 1 floppy, 2 USB hubs, 1 card reader, Klipsch THX 2-1 Sub/Sat speakers, 2 Epson Photo Printers 220R/320R, Agfa Snapscan E-50 Scanner, web cam, Win XP Pro SP-2, Norton AV, ZoneAlarm Pro, GhostSurf, WinPatrol Plus, SpyBot SD, Ad Aware SE, Windows Defender, Spyware Blaster (and still not enough)D-Link router for addition FireWall. Way too much software. Love to copy DVD's and this thing does a pretty good job of it.
I do sometimes (maybe once a week) get a spontaneous re-boot. Not necessarily when I'm doing a certain task or using a certain piece of hardware. Motherboard looks good, caps look normal.(Haven't looked for known problems with the Intel MoBo) Probably a failing mem module or pushing my PSU to the limits. Looking to upgrade to larger PSU.
Love reading the great input from everyone.

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(NT) (NT) You need a new PSU Just to run the Csae Fans.
by ythe1300 / April 29, 2006 9:44 PM PDT
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Power Supply
by RoddP / April 27, 2006 7:45 PM PDT

I am currently running a 450W power supply and starting out with a 350 and having shutdown issues. The computer is custom built with separate DVD/RW and CD/RW's. I has a cassette player, remote control/temp Control, AM/FM DVD, 20 in 1 Reader, and a set of bay speakers. There are about 9 fans in it as well. It was being used in Iraq while I was a contractor there last yr and I needed as much cooling capacity as I could get without going to liquid types. There were a lot of guys there who had built killer systems for whatever reason.

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451 to 550 watts
by marsmithmarsmith / April 27, 2006 10:37 PM PDT

Don't know what motivates the question, but I've purchased "white box" computers (built locally using off-the-shelf components) since 1996.

The major brands have a couple issues. The try to save money by installing a power supply that's just enough to run what they configure to start.

They also don't seem to that disk-to-disk backup is economical, so what they plan for is only one disk. But the only kind of backup that IS economical is backup that users will actually bother to do consistently. So I have three drives, one 50 GB and two 80 GB drives. I have at least two copies everything, and each separate copy is always on a different device.

While 500 watts appears to be overkill for a system like mine (2.4 Ghz purchased three years ago), it makes sense with for a system with three drives, and a paranoia about insufficient cooling.

The other thing I purchase that's "overbuilt" is the cabinet. Since the power supply is enough to support lots of add-ons, I make sure there are two or three fans, and that I don't skimp on their cost so that their noise output isn't a big irritant.

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650watts Arrow Power supply
by elpresidente2075 / April 27, 2006 10:41 PM PDT

Too bad it doesn't produce exactly what it says it's supposed to do. Oh well, for 20 bucks, who can complain? I may mod it though, to cool it more efficiently than the two underpowered fans running in it now.

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i use a 300 W CE power supply
by tazadsldevil / April 27, 2006 10:57 PM PDT

My system
intel P4 (s478) FSB 800 2.8GHZ HT (cpu)
Albatron Px865pe PRO
1.5 gb RAM
120 gb hdd
dvd LG 16 X READER

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350W up in smoke...
by techguy651 / April 27, 2006 10:59 PM PDT

I just had a generic 350W PSU that went up in smoke, literally. I've never seen that before and it look awsome. Smelled terrible though.

I have three case fans, three hard drives, two DVD-ROM/RW, Athlon XP 3000+, Radeon 9600.

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Calculating Wattage?
by techguy651 / April 27, 2006 11:03 PM PDT

Does anyone know how to calculate the wattage a PC needs? I'm looking to buy a new PSU and dont want to get one that's too small.

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just get a 500-watt
by theandy83 / April 27, 2006 11:55 PM PDT
In reply to: Calculating Wattage?

500 watts should be enough for most systems.
unless you got p4 extreme 2 gig ram ATI all-in-wonder 2 or more hard drives and 2 or more dvd drives

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