Modular Power Supplies Less Efficient Say Makers

[tuannguyen]

It's all about power efficiency these days.

Modular Power Supplies Less Efficient Say Makers : Read more

 

[B-Unit]

Glad to see the major players getting behind this. I read a couple of articles online talking about this over a year ago and have avoided purchasing or recommending modular PSUs since.

 

[stray_gator]

PCP&C always discouraged modular psu's - which they also didn't make.
Hearing similar claims from other manufacturers (some of which sell mainly modular units), though, give them more weight and credibility.
I'd still love to see some hard numbers, anyway.

 

[theone1]

If two connectors and pin (male female) add 1 ohm (total) then for a 20-40A current you loose 20-40 Watts.

 

[theone1]

[citation][nom]theone1[/nom]If two connectors and pin (male female) add 1 ohm (total) then for a 20-40A current you loose 20-40 Watts.[/citation]

Sorry My mistake:

R(loss) = 0.04Ohm (2 feet of 20 AWG wire + 2 feet for return ground)
Power Loss = I*I*R(loss) = 40*40*0.04 = 64Watt

This is a power loss of 10% for 650Watt PSU

 

[The Lady Slayer]

I'm not a spambot. Just to make that clear.

Before I bought my modular PSU I did a fair amount of reading and research and in end I decided to go with a Coolermaster Silent Pro 600W. I had heard that Corsair were THE makers of modular PSUs, but in Australia you pay significantly more than the standard US to AU currency conversion due to their popularity. Anyway, in my searching for reviews I stumbled across Jonny Guru, an online reviewer who almost exclusively rates PSUs, and tests them based on many things including whether they are infact 80-Plus.

He gives the Corsairs (MX620W up to MX1000W) between 9.5 and 10, off the top of my head, and gave the CM M600W a score of 9.0, which I was really happy with.

Just google his name if you haven't heard of him.

 

[EQPlayer]

I'm not worried about giving up a few % of efficiency in order to get modular cabling. *shrugs*

 

[brendano257]

I've had two modular power supplies in the past, one of them did fail, although I'm not sure it was because it was modular or not. But if you get something like the Corsair 750TX all you need is a little nook or cranny at the bottom or top of the case to put unneeded wires. (Bottom/Top depending on PSU placement.) In my Antec 900 they actually all fit under the bottom drive bays, which put them completely out of the way and didn't take up any usable space.

 

[Pei-chen]

Make sense. Didn't manufactures also said a single jumble rail is better than multiple smaller rail as multiple rail often creates unbalanced load on the PSU.

 

[shades_aus]

Add a few % more then for the connector to your mainboard and HDDs, floppy, let's not forget the data cables also, I mean, everything takes power. What about the tin legs for the chips and solder used to conduct between the copper tracks and the chips themselves?
You would think they are talking about rubbing two sticks together here!.

Have you actually mesured the difference with a good multimeter? I have, and it says there is no difference. This sounds like bs to me. IF there is any merrit, perhaps manufactures should look at trying different connectors or metals like silver/gold plating.

I think this all started because one manufacturer has the patent on a form of the modular connector and the others don't want to pay.
Why not just design one that isn't patented and standardise it.
All for modular. Cleans up the case nicely.

 

[baddad]

0 Ohm's in one inch of wire is the same as 0 Ohm's in ten feet of wire no significant resistance.If there is any lost in modular PSU 's it's so small it's of no impact, sounds to me like they don't want to make them to cut cost.

 

[fletchoid]

Before everyone starts ripping out their modular power supplies, it would be helpful to have some objective testing to determine the actual effect on efficiency of the modular vs standard power supplies. Even then, if the loss of efficiency is minimal, I will stick with modular power supplies. They allow for a much cleaner case, with better air flow, and if a power supply does fail, or you decide to get a more powerful supply, you just unplug the back of the PS, unscrew the PS mounts, put the new one in, and replug the connections. Much easier.

 

[Guest]

I think I'd prefer the possibility to upgrade or replace my powersupply in case of failure. Also, the resistance added by plugs instead of a hard wire is less than 0,05ohms. Not 1 ohms.
Second: I've been running pc's from 1999 and older. None of these ever had a corroded pin. If they did, the impedance wouldn't go up, because as you plug or unplug the plug, the corrosion gets scraped off, and newer metal will be exposed giving a good connection again.

Though it is true those mod pins are not very surdy, and could break. Especially for testing mobo's that regularly get hooked up on different hardware like PSU's.

If modular pins last 5 to 10 years, about as long as a powersupply does, then I'd say go for modular.
The chances are greater that you'd upgrade your rig with an extra DVD/blueray player, harddisk, cpu, more USB devices, or newer gaming videocard, and need the extra power; or,perhaps, buy a lower power PSU, as newer technology comes out, and smaller die ram/CPU, or newer SSD drives reduces the overall powerdraw.

 

[dirtmountain]

This is what Jonnyguru says (in part)

"There’s been a lot of scare tactics used to convince people to not go with a modular power supply. But the reality is, even at high loads the resistance is quite minimal if the correct measures are taken."

Give us hard numbers, especially since so many modern modular PSUs have the ATX/PCIe/and primary SATA cables hardwired and only have extra peripherals/additional PCIe using the modular cables if they're needed

 

[scook9]

This is interestting given that Corsair just released two modular models that are 80plus Silver rated, that is ths highest ANY of their power supplies have been to date. And as for reliability, they also come with 7 year warranties, also the best ever from corsair. The little inefficiency due to the extra contact is not that bad actually....unless they go with REALLY cheap materials for the connections. Besides, these losses already exist at the component end of the wire anyway, where ALL the computer parts connect.

This in no way discourages me from the Corsair 850HX I am planning on buying as soon as my paycheck comes in. And as others have mentioned, all of the high current connectors are almost always hard wired anyways, so the loss (if any) is VERY minimized as it is.

 

[Shadow703793]

It's all about power efficiency these days.

Nahh... it's about POWER & efficiency.

 

[nickcardwell]

It is hard to find quality non-modular power supplies these days. PC Power & Cooling is a great company for this. I have a Corsair non-modular 450w PSU that works great. Any higher from Corsair and they are all modular. I recently took my rig into a local custom system builder shop to see if they would be interested in purchasing it from me. They told me they were surprised I hadn't melted the little 450w PSU. It's just an E8400 and a single 9800GTX+. The whole system fully loaded only draws around 220w at the plug from my Kill A Watt meter. I can't believe even these seemingly pros buy into the whole 1Kw power supply idea. Most power supplies are most efficient when loaded about 50%.

 

[tipoo]

This has been known for years, has it not?

 

[GenKhan2]

Complete shenanigans! They are likely complaining about the additional cost of making a modular supply. Preying on people's need to be "green" is popular and profitable these days. Allow me to demonstrate.

-I have an Enermax Modu82+ 525W.

-It’s rated at 40A combined draw out of the 12V rails (480W).

-Two of those rails are dedicated to graphics cards.

-Those rails connect to the graphics cards via twelve pairs of 18AWG wire into what is roughly a Molex Mini-Fit Jr connector.

-I looked up the average resistance through mated connectors after 20 insertion/extraction operations from Molex. Here’s the results arranged by type of pin:

Resistance per connected pin pair
Gold plated brass = 2.62 mohms
Tin plated brass = 3.09 mohms
Tin plated phosphor bronze = 2.45 mohms

So the modular nature of my power supply adds two times the resistance listed above to each circuit. However, there are twelve circuits in parallel. So the resulting added resistance is the figure listed above divided by a factor of six, as shown below:

Total added resistance
Gold plated brass = 0.437 mohms
Tin plated brass = 0.515 mohms
Tin plated phosphor bronze = 0.408 mohms

Let’s assume I’m able to pull 100% of the total rated 12V current for my graphics cards. So here’s how much power is consumed by the pins:

Power wasted due to resistance of pins
Gold plated brass = 0.699 W
Tin plated brass = 0.824 W
Tin plated phosphor bronze = 0.653 W

Now for the nail in the coffin of their argument. Out of the imaginary 480W total power consumed in my example what percentage is wasted by the pins?

Percentage of total power wasted
Gold plated brass = 0.146%
Tin plated brass = 0.172%
Tin plated phosphor bronze = 0.136%

Yes, a modular supply is less efficient. It’s less efficient, in my example case, by a massive 0.227% on average. Completely negligible. By modular kids. Get your money's worth.

 

[computabug]

To me, it's not about efficiency... it's about reducing the chances of failure in my system . I just hide the extra wires behind my mobo tray. Besides, I'm so forgetful that I'd loose those extra wires when I need them

 

[mogle]

well here are two thoughts that i'm sure everyone else was thinking. either put more power to the modular lines to compensate for the drop or make the common lines that 98% of us will use in every build an uninteruppted wire. then make the rest modular. all someone realistically needs is a couple mobo wires and a few for our sata devices. add a couple uninterupted pci express wires to the high wattage supplies and that should do it. if its something that you wouldnt want then read about the psu before you buy it. not a big deal.

 

[ossie]

It's more a problem of reliability than efficiency. Many insertions/extractions can lead to mechanical wearing off of the contacts, leading to poor contact resistance.
What those efficiency "gurus" tend to forget is that at the end of PSU wiring there is always an identical connector (M/B, G/C, etc.). OTOH older HDD/ODD 4 pin AMP MATE-N-LOK connectors were notoriously unreliable, wearing off fast (mechanical fatigue affected spring loading, locking being based on friction).
"Due to their look, convenience, and cost savings for manufacturers, modular plugs have become a popular power supply feature."
What cost savings? A connector and it's crimping will always cost more than straight wire.
"Worse yet, modular plugs utilize delicate pins that can easily loosen, corrode, and burn, creating the potential for a major system failure. That's why professional system builders specify uninterrupted wire!"
They should push for the same thing at M/B and G/C manufacturers. Their power connectors are the same Mini-Fit Jr. ones. Let's solder all those PSU wires to the PCBs.
Tuanny boy, try to use your head, before parroting all this bull$hit.

 

[redgarl]

As an electrical engineer, I can admit that any connector will reduce efficiency, but nothing more than probably 2% in really extreme situation.

It's about 1% in optical wiring, so hell, electricity should be less than that.

 

[blarneypete]

[citation][nom]Tuan[/nom]So in the end, you have to choose: do you go with a modular PSU for cable management and appearance, or do you spring for a hard-wired PSU?[/citation]

Here's a thought: How about Tom's Hardware do what they do best.

Do a formal test using proper equipment and competent testers, and then write an article about it, and then post that article on THG. Then ask readers the same question. Maybe then people could make an informed decision.

 

[jeverson]

So Tom's... is this the prelude to another great review/article? Would love to see some solid comparisons.

On a personal note... I have really liked the idea of modular since I hate clutter in my case and non of the manufacturers seem to really pay attention to just what connections people need or use anymore. For example... who uses molex connectors anymore? Everything is PCIe and SATA now. For some reason they don't seem to sit down and logically think about what kinds of connectors people need at certain power levels. This results in there being cables that have no use and waste space and interfere with air flow. I think people would be less concerned about the modular issue if they new they were getting the connections they needed for the wattage they are using with having a lot of leftovers.