Choosing the Right Power Supply

C

clarkkent57

Guest
First things first. If you've got a poor-quality and/or faulty power supply, nothing else you do will work to solve your problems. Stick to the basics before you go further...The short answer is to buy a hi-powered, brand name supply, like the new ENERMAX line (430 W or higher) or ANTEC True550. Almost nothing else will do with today's computers. In over 30 years of electronic/computer service, I have found that 85% or more of problems were power-related.

If you want to know more, read on...


Choosing The Right Power Supply

If you?re reading this, there?s a good chance that one of my colleagues or I believe that you could be experiencing problems with your power supply, based upon the symptoms you mentioned in your post, and provided you with this link. Relax, you?re not alone. In 30 years of electronic and computer troubleshooting, I?d say that the majority of the electronic, mainframe, mini, and microcomputer problems I?ve diagnosed and repaired were with the basic power the problematic device was receiving. The symptoms often included random reboots, crashing, the BSOD, lockups, etc.

(As the national support technician for few major computer service companies, working US Defense contracts, I was often the person that had to fly in and correct the problem, or ?walk through? the on-site technician as he closely followed my instructions. I achieved success in my career by carefully reading the manuals, knowing where to go for more information that was otherwise unavailable to me, and/or systematically troubleshooting until the problems were discovered and repaired. I never had the option of giving up.)

The most overlooked component when building or upgrading a PC is the power supply unit (PSU). Some people use their old case and PSU when they upgrade. Some use the PSU that came with their new case. Some people even buy a new PSU. And most inexperienced builders all make the same mistake: The PSU that they?re trying to use is simply inadequate for the job.

Suppose you?re upgrading to a new motherboard, CPU, ram, and video card, but still using the old case and PSU. It?s most likely that you?re upgrading in order to build a machine that is more powerful, faster, has a more colorful display, can number-crunch more quickly, play the latest games, etc. These gains in performance all have one thing in common: They require more raw power. However, have you thought about where that power comes from?

Suppose you?re building a new system with a new case and PSU. Has it occurred to you that the company that you bought the case/PSU from might make more money if they skimp on the supply, even if the supply has a large wattage rating? Most bulk power supply manufacturers don?t make good PSU?s. They use older, cheaper technology, and slap on labels that represent the PSU?s peak outputs, and not their continuous output rating. These companies are intentionally misleading you in order to sell you an inferior product. Brands I avoid when building/repairing my friends? and family?s computers: Allied, Q-Tec, Chieftech, and many others.

For those of you who bought a power supply separately, did you know that you?re only supposed to run a power supply continuously at 30-70% (with 50% being optimal) of its continuous rating for maximum efficiency (which means less heat to you)? Most inexperienced builders either buy PSU?s that are matched to their equipment?s continuous power usage, or ones that are even less powerful than they need. Why? Because they?re trying to save money.

I mean, what?s the fun in a power supply? You don?t get any games with it, there?s no more storage, hardly ever any more bells and whistles, etc. A power supply is boring, and it?s supposed to be, because it?s supposed to provide a stable, reliable platform upon which the rest of the equipment can easily access the amount of power it needs, and when it?s needed. In almost EVERY review of powers supplies, the same point is stressed: Better safe than sorry.

But what does safe vs sorry mean? It can mean that you don?t have to waste money on the wrong PSU in the first place, but it can also mean that you don?t have to replace your expensive ram, CPU, video card, etc. NEEDLESSLY, or because your cheap PSU destroyed them. What? A cheap power supply can wreck your computer? YES IT CAN. A cheap power supply can cause thermal damage, not only from the heat it produces, but also the heat it can create in your components as well. RAM is especially sensitive to heat, and there?s RAM in your CPU, your video cards, and, well, your RAM too. A cheap switching power supply, run at its maximum, or peak, continuously can also destroy components by creating RF (Radio Frequency) signals on your power rails, signals which the components on your peripheral devices were not equipped to handle in the first place.

So this begs the question, how does one choose the right power supply? I?ll illustrate this using my own PC as the example. This is my setup that I use for video processing:

K7N2G-ILSR
Athlon 2500+ Barton @ 2125Mhz
AMD Retail Heatsink/Fan
2 - 512MB DDR333 w/Thermaltake Spreaders (slot 1&3)
MSI TV@nywhere Video Capture
ATI Radeon 9600
120GB Maxtor DiamondMax Plus 9 SATA
30GB Quantum IDE
TEAC DV-W50E DVD/CD-R/W
BTC DVD-ROM Drive
Artec CD-R/W


Using this Power Supply Calculator link:

http://www.jscustompcs.com/power_supply/

I plug in all my equipment values, but some of this can be a little tricky. For example, since I often run the CPU like an XP 3000, I choose the 3000 as my processor; it?s the same chip run at the faster rate. I also choose the ATI Radeon video card, and I select the RAM wattage for 2 sticks of DDR. I also choose every card I have, like my video capture card, but I also select the boxes for the separate cards that correspond to the functions that my ILSR provides as well (and that I use), like sound, USB, Firewire, NIC, etc. ?Although I use the onboard SATA controller, I don?t select the SCSI PCI card, because, in truth, I?ve probably made up for it by selecting all the other corresponding devices, including cards that the motherboard replaces. I check the boxes for the fans and drives I use, and I?m done, right?

Not yet.

I just remembered that I plan to upgrade soon, so I go back and change the values to reflect my impending changes. I mean, I want to make sure that I have enough power to begin with so that I don?t have to replace the power supply again, right?

Ok. Done. I look at the bottom and see that it tells me that I need a 468 watt PSU. So a 480 watt supply will do, right? Wrong.

Remember that, for efficiency, long-life, and less heat, you want your actual power consumption to fall between 30-70% of the PSU?s rating, so add 30% (minimum) to the 468, and you get 468 + (468*.30)= 608 Watts! Holy Cow!

However, I?d only need a 608-Watt supply if I was using all the devices at once, and I don?t. But, in truth, with video and audio processing, I often get close when I process, burn, and monitor at the same time. (Hardcore gamers also get close a lot, as they blast the sound and push that video to its limits.) So, let?s take off 10% (maximum) of 608, for a total of 541 Watts.

I need a 550 Watt supply, but not just ANY 550 watt PSU. I need a supply that can give me enough power on the critical 3.3, 5, and 12V rails combined. I also want a supply from a trusted, name-brand manufacturer, so I start hitting the many online reviews. Here are just two from Tom?s Hardware:

http://www6.tomshardware.com/howto/20030609/index.html

http://www6.tomshardware.com/howto/20021021/index.html

Read these in their entirety. I didn?t post them because they?re pretty links.

In the end, I chose Antec, because they?ve got the reputation, the recommendation, and because the Antec True550 has better specs than the rest of the 550 Watt competition. I also bought it from a reputable company I found on Pricegrabber.com, for the lowest price I could find, $95.00 shipped to my door. (In truth, I wanted two mini-redundant supplies, like the hospitals and military use, but they were too expensive.)

The result? Not only are the random reboots, crashing, the BSOD, lockups, etc., gone like magic, but I also now have ?peace of mind? in that whatever might happen to my equipment in the future, I know almost for certain that the PSU is NOT the problem. I also bought an UPS, because the East Coast Blackout proved to me that even the Antec True550 isn?t going to provide me any power for emergency shutdown if it doesn?t get its power from somewhere.

Even if your problem doesn?t lie in the PSU completely, it gives you a GREAT platform for troubleshooting further. If you?re not reasonably certain that the supply is the cause, borrow one, or buy one that you can return once you?ve solved the problem. But, above all else, BUY THE RIGHT SUPPLY before you do anything else! Otherwise, you could be plugging and unplugging components, buying and blowing up expensive memory, and causing even further damage, until you give up or die.

I mean, I assume you built your own system to enjoy ?more bang for your buck,? right? What?s the fun of a random reboot in the middle of Unreal Tournament 2003?

William Hopkins
Former Staff Sergeant, USAF
B.A., B.S., with Honors
The University of California, San Diego
Clarkkent57@hotmail.com

P.S. It should be noted that while Enermax, ThermalTake, Zalman, Fortron, and others make great PSU?s, and I compared and considered them, the Antec still won out overall in my critical evaluation, like it did in so may others? reviews. You?d probably be ok if you went with another reputable manufacturer as listed above, but pick a supply that gives you at least 230 watts on the 3.3 and 5V lines combined, and still meets the 30% criteria as stated above. Remember, if the manufacturers don?t give you maximum combined specs up front, they?re untrustworthy right off the bat. With power supplies, you definitely end up getting what you pay for. Don?t say nobody warned you.

P.P.S. Update! After recent developments, it looks like Enermax is the leader, but only the latest line of PSU's.
 
Sorry to say, even when it has the MSI logo....it's still a split rail and I would NOT buy it myself.
PS, it's only MSI USA that sells PSU's to my knowledge.

If it works it works, but I wouldn't buy it.....sorry MSI USA :lol_anim:
 
Ahh I wish that I had come across this article sooner. I had to learn the importance of choosing a good power supply the hard way. I built this awesome gaming rig, a brand new P4, MSI Neo 3 board, and it was loaded. Well I brought the computer up to school with me here where the power is kind of flakey and old and yep I fried almost every piece of hardware on the computer. I RMA?d the board and waited the long wait to get a new on. Guess what? my processor was toast as well, so it just blew the board up as soon as it came in?. Shortly after that incident I had another PS blow up and almost catch the house on fire?. Needless to say, I check the power supply ratings carefully and choose good power supplies from Thermaltake Antec and Enermax and I have not had a problem with computers since. It was a tough lesson to learn and almost cost an insurance policy. Be sure to not only check the PS ratings, but the safety features that will protect your precious expensive components, and your property. I have never failed to overlook a power supply again : ) I recently ordered an Mbox barebones for a new server (finally after almost a year!) to get my personal web server running. The Mbox comes with an Austin PS but I will be replacing that with a quality Enermax to ensure that I don?t ever have a blown PS wrecking my day ever again! Do yourself and your customers a favor and put a good PS in there! It?s something that should not be overlooked and you will be glad to have a stable reliable computer, if I hadn?t overlooked the PS when I built my computer I would have easily saved thousands of $$$$ I think that the ratio of about $140 to $2000 is an easy choice.  :rolleyes_anim:
 
I also recommend that you get a UPS, uninterruptible power supply, especially if you bring a computer to a dorm or whatnot.  Not only will a UPS clean and regulate the power coming into your system, it will help protect it from surges and drops better than the best power strips and will keep the machine running in a power outage which will  allow you to shutdown your system properly in a blackout.
 
;) Yes I also purchased a UPS after that little incident?. It has saved me a few times with a tripped breaker while typing some assignments.  :rolleyes: It annoys my roommate though when it trips and beeps but at least my expensive stuff is protected?Which is more than I can say for all of the laptops, computers, and TV?s that are plugged in here. It?s a short lifespan on electronics in this building if they are unprotected. I?ve had to fix countless computers with (GASP!) Blown PS?  :noidea: Plus the local computer shop has some pretty decent UPS's here for around $35 so you can't beat that. Ahh live an learn, fortunately I have had some stable power up until this point here (Spoiled)
 
Since I am upgrading my system with a new vid card, a MSI 7900 GTO, I thought it would be wise to purchase a new PSU also.
Actually there are 2 PSU's that I already have in mind:

1. Enermax Liberty DXX 500 > http://www.enermax.com.tw/english/product_Display1.asp?PrID=4
2. Be Quiet Dark Power Pro-530W > http://www.be-quiet.net/be-quiet.net/index.php?action=td&StoryID=21

As you can see both PSU's are modular ones....is there anything that speaks against modular PSU's?
Are these PSU's ok, which would be the better choice or what other (modular) PSU's would you recommend for the following setup:

Intel Core2 Duo 6400 @ 2x 2.13 Ghz
Zalman CNPS 8000
2x Aeneon 1 GB @ 667 Mhz (4-4-4-12)
1x WD 250 GB IDE
1x NEC DVD-RW
1x LG DVD-ROM
MSI 7900 GTO @ 7900 GTX

I hope you guys can help me to buy the right PSU for a change.... ;-)

Thanks in advance,
Bob
 
The Enermax Liberty Power Supplies have some very good reviews. I had decided on the Enermax Liberty or the Corsair I ended up purchasing. It came down to I found a very good deal on the Corsair.

I have never heard of the other supply so cannot comment on it.
 
So I don't need to worry about the fact that this Enermax PSU is a modular one??

The thing is that I've read an article posted on this forum basically saying that modular PSU's are crap. Unfortunately I cannot find this post / article anymore, I think it was from a certain PSU brand that I don't know and don't recall....
 
Thanks Vernonion!
Yes, that was indeed the article I had in mind!
But is this info still accurate? Is it really a bad idea to buy a modular PSU? I really want to buy this PSU and all the tests I have seen are very positive >>
Enermax Liberty DXX 500 > http://www.enermax.com.tw/english/product_Display1.asp?PrID=4

 
Why would it change, even stereo buffs insist on gold plated connectors to eliminate noise in their speakers. If you have enough amperage I guess you could reach a point where modular connectors made no difference. I have heard that the Enermax that you are looking at is really a single rail, but they do not really published that anywhere so how do you really know what you are getting? At the end of the day you don't really know if it will work with your particular set up until you or someone with your exact same setup trys it and has no issues. Just remember that the 7900GTO graphics card and minimal equipment will need 22 to 26 amps and you can't always add two rails together to get that. Then add more for extra drives, fans, usb devices, lights and resistance across modular plugs and you see where this is heading.
 
Ah, just the topic I was looking for.  ;D

I have just upgraded my brother in laws mobo, cpu and ram from a MS6511 mobo to a MS865GM2 mobo. It starts and stops in seconds, sometimes the heatsink fan spins once and it stops.
Having read through this thread I suspect that the eight year old PSU is not giving enough juice..

It's a FSP 300-60PNA
3.3v - 15A
5v - 30A
12v - 15A

I have upgraded it to a 2Ghz Celeron with 1Gb of ram and a 512Mb Graphics card. I guess I should go for an Antec 500 orsomething?

Kevin

(Disregard the info in my sig as this is my brother in laws)
 
Energy saving tip #2, put your machine in hibernate or shut it down if it isn't being used for long periods(many hours) of time.
 
u cant beat this PSU:

http://www.pcpower.com/power-supply/silencer-750-quad-crossfire.html


actualy its must be named not 750W , but 825W. as long 825W is Peak for this PSU, and 750W continuous.
and its have 60A on +12V (single rail) continuous /its bout 66+A peak, more than my OCZ 1010 GameXsteram have on combined 4 ralis. (20A peak on each rail, or 66A peak combined)
 
Hi, I came here looking for a power supply calculator for this motherboard and a dual core 3.0GHz 2GB ram 1 sata hard drive and a 8600GT Extreme graphics card. I will use this for small games but mostly work.
The link  ... http://www.jscustompcs.com/power_supply/ ... is not working for me.
Thank you MSI forummers, have a nice Christ mas ... is Noah's Ark on the Mountains of Ararat in Turkey...I think it is.
 
But remember, those recomendations are for a minimal system(and covering an array of CPU requirements).  If you have multiple PCI/PCIe cards, multiple HDDs and multiple ODDs, special lighting, more than a couple of fans, or other additions, you may want to pad the amp requirements.
 
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