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Read the power supply faq's still a tad confused

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June 18, 2008 2:39:09 PM

Ok so I've read, the psu myths, 101 and the main faq. However, I want to build a new pc, the amp requirements of new graphics cards from psu's is confusing me. I'll give you the full specs of a pc I'd like to build:

Intel E8400
MSI Geforce 9800 GTX
2gb kingston hyperx(2 x 1gb)
160-250gb HDD(1 hard drive)
MSI P45 Neo-F

Now I've read that this nvidia 9800 GTX requires between 26-30 Amps to run properly. Now I've read in the myths thing, that multi 12V rail PSU's are a thing of the past and/or crappy vs single 12V rail ones. However, I have yet to find a PSU , within my budget that has a single 12V rail with 26-30 Amps.

So now for example, I've found a 480 watt psu with a single 12V rail with 15 amps on it. Will I be able to run a 9800 GTX on it or not, seing as it needs 2 6-pin power connecters, perhaps it draws from the 12V twice. I don't understand. Do I really need a PSU with a single 12V rail with 30 amps on it?

I can find ones within my budget that have 2 12 V rails, with which am I better off? Am I missing something here?

PSU I'm talking about: ADVANCE ATX-5012


I can spend no more than 30 euros on a PSU. I was hoping to get one with a case so I don't have buy one, found one with a 550 Watt PSU attached, however, don't know if it's up to scratch. From this website:
http://novasia-technology.com/HTML/Decoupes/case2008.ht...

The Case I'm looking at is an INNOVAXX W6133BS, so I assume the PSU attached is an INNOVAX and is probably one of thte 550 W PSU's on their site, which seem to have 22 AMPs on 1 12V rail.

http://novasia-technology.com/HTML/Decoupes/PSU2008.htm

Thanks for your help.
June 18, 2008 2:46:07 PM

Also I'm not looking to upgrade to SLI in the future, or add multiple harddrives, or dvd drives, or soundcards, or water cooling, no multiple usb devices. Just what's needed. So what kind of PSU would you recommend?
June 18, 2008 3:02:12 PM

I picked up the 650 watt Corsair TX PSU for $79 at Newegg a while back. It has a single rail and works great.

Keith
Related resources
a b ) Power supply
June 18, 2008 3:11:40 PM

No the 9800gtx requires 24 amps or more total on the 12v rails. If you can't afford a good psu with 24 amps on the 12v then getting a psu with multiple 12v rails would be better. keep in mind that the amps on all the 12v are combined to give you your total amperage.

I would scale your build back to a 8800gt and use the money saved on a better psu like te one that kdw suggested. crappy psu like the ones that come with the cases can break your system.
June 18, 2008 3:14:24 PM

I don't know much about the PSUs you have linked.

You may want to consider looking at the ANTEC SONTATA Cases.
They come with a decent built in PSU.

You may also want to really examine your other part selection.
A Cheap-O PSU is never a good option.

Perhaps an E8200 instead of an E8400 would allow you to buy a proper PSU.
June 18, 2008 3:27:55 PM

Better to buy a good PSU separately from the case. A cheap one can make your system go into black smoke. A good PSU is cheap insurance on your system. It is also the heart of your system. You want it to work properly. Many people underestimate the importance of a good PSU.

Top Tier PSU:
http://www.tomswiki.com/page/Tiered+PSU+Listings?t=anon

http://www.xtremesystems.org/forums/showthread.php?t=10...

http://www.jonnyguru.com/forums/showthread.php?t=1460

Silent PSUs
http://www.silentpcreview.com/article699-page1.html

AMD Certified PSUs (Single+Crossfire):
http://ati.amd.com/online/certifiedpsu/index.html

Certified SLI-Ready Power Supplies
http://www.slizone.com/object/slizone_build_psu.html
a c 144 ) Power supply
June 18, 2008 4:39:49 PM

1830330,1,333714 said:
Ok so I've read, the psu myths, 101 and the main faq. However, I want to build a new pc, the amp requirements of new graphics cards from psu's is confusing me. I'll give you the full specs of a pc I'd like to build:

Intel E8400
MSI Geforce 9800 GTX
2gb kingston hyperx(2 x 1gb)
160-250gb HDD(1 hard drive)
MSI P45 Neo-F

So now for example, I've found a 480 watt psu with a single 12V rail with 15 amps on it. Will I be able to run a 9800 GTX on it or not, seing as it needs 2 6-pin power connecters, perhaps it draws from the 12V twice. I don't understand. Do I really need a PSU with a single 12V rail with 30 amps on it?

PSU I'm talking about: ADVANCE ATX-5012

said:

Yet another response ... :) 

ATX-5012 :pfff:  Read the label. Label says 480 watts max. In the lower part of the label, it says "Combined load 380 watts ". This is obviously a label written by the marketing department, not the engineering department.

You can find all kinds of system power calculators online. Here's my personal estimate (based on published power consumption figures and personal measurements based on Gigabyte P35 and eVGA 680i motherboards) of what you need:

9800GTX - 12 v @ 9 amps = 108 watts
E8400 (OC'd) - 12 v @ 8 amps = 96 watts
Motherboard - 12 v @ 2 amps and 5 v @ 3 amps = 40 watts
2 GB memory - 3.3 v @ 3 amps = 10 watts
1 HD - 12 v @ 1 amp and 5 v @ 1 amp = 17 watts
DVD writer - 12 v @ 2 amps and 5 volts @1.5 ams = 32 watts
Case fans - 12 v @1 amp = 12 watts

Absolute minimum power is about 315 watts. But that's not the real problem. You need at least 23 amps at 12 volts. And that assumes that you are operating the 12 volt section at 100% load. Not a good idea. :non:  It is not good for reliability or stability.

You should get a PSU with 28 to 30 amps on the 12 volt rail(s). That requires a good 450 - 500 watt PSU.

You have two real choices. Get an inexpensive PSU and risk replacing it or do it right the first time.

If you are on a really tight budget, one solution is to get a less expensive video card or motherboard and put the difference toward a better PSU.
June 18, 2008 4:55:16 PM

You cannot get PSU for 30euros for Your build. Save money buying 8800GTS instead of 9800GTX, difference is not so big. And use saved money for a decent PSU Like corsair VX550, or at least VX450
June 18, 2008 5:01:39 PM

Ok thanks for the helpful responses, unfortunately, can't get a lot of those models in france, and ordering from the states will just rocket the prices. However I did find this psu:

http://novasia-technology.com/IMAGES/big/P530S2.jpg

It's 530W 2x12V rails PCI-E x 2 etc you can read the box. May not be a known brand, but it's french, and just cause it's new doesn't mean it's ****. However, I'll still need to see the Amperage in the shop, but I think it'll be up to scratch.

Ideally, I'd be able to get a good PSU if I could just buy a PC Case without a god damn power supply, I don't understand, in France, you can get cheap cases with PSU's, but remove the PSU and the price doubles. It's crazy. All I want is a cheap nasty PC case for about 15 euros, than I can throw in a good PSU. I'll try go to the shop and ask them if they can remove the PSU in a case and replace it with this one I want to buy, seing as they sell this PSU. Maybe then I can get it cheap. It's my birthday soon, do you think they'll give me a discount for my birthday?
June 18, 2008 5:10:08 PM

Don't get that PSU.
Get one that will not fry your system.
All the advice here is true and good.
You can't get a good case and psu, together for your budget.
Use an old free case and get a BRAND NAME PSU. Min. 500w
That's why we build our own pcs. The ones at the stores always come with some POS PSU. If you want to actually use that vid card, you'll need a brand name psu, no way around it.
June 18, 2008 5:12:56 PM

I'll give you a tip for your b-day.
Try newegg.com, I can't imagine why you couldn't buy from them, using American$$$$(exchange it or use your bank to make a cashiers check). It may be a hassle but the PSU is VERY important!!!
June 18, 2008 6:06:23 PM

Can't buy from newegg, they don't ship internationally, and that corsair PSU is 104 euros, way too expensive, also, it's modular, read it was waste of time, don't need that. Thanks anyway. What's wrong with this one? Are you knocking it simply because you don't know the brand name or because you know axxyon is crap? http://novasia-technology.com/IMAGES/big/P530S2.jpg

Also, not that I'm overly experienced, but I think you guys are over-exaggerating when you say a PSU will fry your machine. A PSU that's not powerful enough, isn't going to fry the components, the machine may simply not work or be unstable, or the psu might pack up. But I've had a no name brand PSU in my current machine for over 6 years, and it hasn't fried anything.

Look I'll check the Axxyon out, see if it meets the requirements, I don't plan on doing any over-clocking I have very few components, I will probably not even have a cd/dvd rom installed. I'm not a frequent upgrader, so I'll still be using this same pc, after nvidia has released another 5 generations of gfx cards. Should be sufficient, at worst, the pc will be unstable, I'll make a plan. Thanks for all the info anyway, I appreciate it. If all works fine I'll make an update and A-Ok the PSU.
June 18, 2008 6:11:27 PM

Well I when I made the statement I was thinking about local pc component shops, ordering stuff will cost me more money, plus there are tons of web-sites in france just like the ones you've posted that are extremely unreliable, in terms of transport, refunds if the product is damaged, sending the right stuff, etc.. the list goes on.
June 18, 2008 6:14:43 PM

The PSU is the last place you want to "cheap-out" when selecting components for your new PC build. The PSU is the foundation of the system, and its performance can affect every other component - CPU, motherboard, video card, drives, etc. A poorly-designed or improperly-sized PSU can result in erratic, unstable operation, or it could fail and destroy other expensive components in your system.

You said "Also, not that I'm overly experienced, but I think you guys are over-exaggerating when you say a PSU will fry your machine. A PSU that's not powerful enough, isn't going to fry the components, the machine may simply not work or be unstable, or the psu might pack up. But I've had a no name brand PSU in my current machine for over 6 years, and it hasn't fried anything. "

How do you know if an undersized PSU isn't going to fry anything? Most of these products are designed as absolutely cheaply as possible; good design, quality components, and robustness costs money. I have designed electronic switching power supplies, and know what happens at a component level.

Just go ahead and "bite the bullet" - buy a PSU from a tier-one supplier and bask in the warm feelings that come from knowing it won't blow up and take the rest of your computer with it. If you can't afford one now, then take a step back on the video card as suggested in a previous post, or just wait and save a little more money.

PS - I am an electronic design engineer with ~30 years of experience, and have been building my own systems since the 80386 days. I selected a PC P&C Silencer 750 Quad PSU for my latest system - 60A on the single +12V rail.
June 18, 2008 7:41:34 PM

I am not saying that it will fry other components, but it might. Or it might fry itself of overheat and make lot of noise. or burn itself. I had one of my friends who did not want to spend money on PSU when I was buildig PC for him and I could not convince him So he choose cheepass 650W power supply.That was unning very hot and making lot of noise when PC was under load. And it packed up in 2-3 months. Luckilly it did not take anything with it. After that he let me choose new PSU. If remember correctly I got him 600W Thermaltake and it still works fine after 1.5 Years. I do not know anything about the one You choose but it seems to have too little connectors for the listed power??? Only 2 sataand 4 molex. Seems like a old design. You should be looking 6 of each on modern power supply or more of sata than molex. Also beefy single rail is better than two rails. Multiple rails was just a marketing thing year ago.
Save Yourself a dissapointment and get a good known PSU. The money You save going from 9800GTX to 8800GTS will cover difference in PSU costs and You will not loose much (if any) of perfomance. Obviously choise is Yours.
June 18, 2008 7:57:35 PM

Ok, but I can't find a cheepass PC case without a power supply, I refuse to pay for a case with a power supply, and then buy another power supply. I can't find one that's really cheap. I'm talking 10-15 euros cheap. Perhaps I can make one out of wood.
June 18, 2008 8:10:31 PM

Or buy one with a PSU and sell PSU on e-bay.
June 18, 2008 8:46:33 PM

Jimnast said:
Ok thanks for the helpful responses, unfortunately, can't get a lot of those models in france, and ordering from the states will just rocket the prices. ...


I am based in the UK so a pretty similar situation to you re suppliers!!

You can order stuff from the USA:
http://www.performance-pcs.com/catalog/index.php
They take Paypal and ship worldwide US Postal Service (v. cheap - often with no import duty here in the UK!! Heh heh). I buy stuff from Hank all the time. Very nice range of PSUs as well...

You can order stuff from within France at reasonable prices:
http://www.pc-look.com/
Again I order from PC-Look fairly often. They also have a good range of PSUs. They are based in France.

RANT
Don't be an idiot... Getting expensive gear and running it off a cheap PSU is a recipe for instability and ultimately (the possibility) of blowing one of those expensive parts up. Cheap PSUs age much faster than good quality ones (e.g. Corsair with 105C rated capacitors). IT'S A FALSE ECONOMY!! Buying a cheap PSU is like playing Russian Roulette with your system components!!

Save up your money if you can't afford the gear now!! Buy it on a 0% credit card and pay it off...
/RANT

Do get the 8800GTS - get an unbranded Nvidia own model to save money (MSI branded copy = waste of money as no extra warranty). The 9xxx series is a joke don't bother except for perhaps the 9800X2 model....

Get a cheaper CPU and overclock. The E4500 is on sale at pc-look for 92 Euro (way cheaper than a Wolfie). Overclock that to 3.0Ghz and you will still have a stonking system. If you can't afford a high-end system then don't try to buy 1/2 of one (the wrong 1/2)!! An overclocked E4500 won't hold back the gaming performance of a 8800GTS.

I read that Crucial Ballistix is one of the best overclockers for the money. Don't see any reviews for Kingston HyperX on my favourite e-tailer (www.overclockers.co.uk). Its about the same price anyway...

Bob
June 18, 2008 9:06:05 PM

Ok, thanks once again. I could keep my current case, the only problem is that the power supply hangs vertically instead of horizontally in new cases, so it sits 3/4 the way on top of the cpu fan. There's about 2-3 centimetres distance between the PSU and the CPU fan. Do you think that will be a big problem if I buy this new pc?
June 19, 2008 12:10:36 PM

Not sure if the PSU fan is facing the CPU or not.
The PSU sucks air in, so does the CPU. It's kind of like a conflict with only 2-3 cm available if the PSU fan is facing the CPU.
The computer will work, but you may have high temperatures.
Otherwise it should be okay.
June 19, 2008 3:07:10 PM

Ok well I'm sure I'll be able to turn the PSU around to face the other way, but then I'll have to leave my case open or cut a massive hole in the side. However, if you buy one of these 120mm PSU's with the new style case where the PSU is horizontal, if the PSU fan is facing down, it will be sucking in air from inside the case, which isn't good, but if it's facing up it will be flat up against the roof of the case sucking nothing but plastic. Am I missing something, or do you have to cut a hole out of the top of your case?
June 23, 2008 12:24:13 PM

Normally PSU fans suck air from the case and expel it out the case.
The PSU fan should not be facing the roof of the case.

June 23, 2008 2:00:56 PM

evongugg said:
Normally PSU fans suck air from the case and expel it out the case.
The PSU fan should not be facing the roof of the case.


There is nothing wrong with putting it with an air-intake facing up if you can mount the PSU that way (a lot of cheap cases don't have a detachable PSU plate that can be reversed)... Just have to drill-out out a blow hole in the case above the PSU (with a hole-saw)... Isn't it a bi-atch when you've got a steel case!!

That would be a more stable arrangement for the PSU (especially if it is a cheapo model rated at 25C) if you are aircooling your components...

Hmm just a though... :pt1cable: 



Jimnast > I am really confused by what you mean !! PSUs are always mounted horizonally (or on their side). NEVER seen one mounted vertically yet - ya whaaat!!! :pt1cable: :pt1cable: :pt1cable:  Generally PSUs are fan down mounted where-ever they mount (newer style in a bottom compartment or older style at the top of the case)...


Bob
June 27, 2008 3:22:09 PM

"Also, not that I'm overly experienced, but I think you guys are over-exaggerating when you say a PSU will fry your machine. A PSU that's not powerful enough, isn't going to fry the components, the machine may simply not work or be unstable, or the psu might pack up. But I've had a no name brand PSU in my current machine for over 6 years, and it hasn't fried anything."


*** hah *** the first time the power goes out 3x in a row, you'll be sorry that you didn't get a PSU w/stronger capacitors 'n such! It WILL leak through to your mobo and beyond, FRYING components. BROWN OUTS AND DIRTY POWER get through no name PSUs and if you want to use the hardware(specifically the vid card) you have expressed, then it will happen a lot easier than with just the conventional equipment you've been using thus far. Myself and others have given this advice too many times and people that don't follow this advice ALWAYS have problems they can't figure out... hmmmmm they replace the PSU and the problems go away. Do you have a super bad a__ surge protector? Battery back up? w/o those things your cheap PSU coupled to that hardware will FRY it once the lightening strikes. Don't take my advice though, I don't know anything about this stuff.
!