Discussion PSU recommendations and power supply discussion thread - Tom's hardware

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For those confused, the S12ii has sub-par electrical performance and lacking important protections.
Very low voltage regulation on the minor rails, and poor performance in crossload: https://www.techpowerup.com/reviews/Antec/HCG-520/
The Hy510n Protection chip the S12ii uses lacks OCP completely, UVP on the 12V rail, and no OTP in the PSU. All of which are important protections.
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I don't want to argue this point. But I do want to give a counter balance to what was mentioned. First, while the link is nice, it is to an Antec model of that PSU. It's possible they changed (minor) things to suit what they wanted to sell or hit their price points. The S12ii IS an older group regulated design. I'm not denying that. But some of the things that were pointed out aren't an issue, or isn't likely to be seen. Bad crossload? In this day and age you aren't likely to see a system with 1A on the 12V rail. In the crossload that matters the unit did fine. No OCP? You linked a single rail PSU where OPP would basically serve the same job as OCP. Voltage regulation? Using the unit linked, the 12V rail was still 1.1%, while the NO rail went out of spec. The minor rails might not have had the tightest regulation but I'm not sure that's a horrible thing. More so for such a cheap unit.

OTP is important and it would be nice to have. If you don't put your PC in a box however and keep the fans going you'll never see the temps needed to cook it however. The EVGA series was mentioned, here is our review on the 450BT.

https://www.tomshardware.com/reviews/evga-450-bt-value-psu,5605.html

EVGA claims a low 30°C temperature rating for sustained full-power output...(jumping to final page.) the 3.3V rail's transient response is really bad...The Teapo capacitors that we find inside are fairly low-end...Lower than 17ms hold-up time. Cables with thinner than recommended wires. Overrated MOV in the transient filter
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There is a lot to not like about that unit as well. I agree that for a basic PSU it, like the CX450, or even the S12ii are good units to buy. Getting the cheapest of them is "best" if the budget can't be increased. But to constantly complain about one and suggesting another equally bad unit is better doesn't make sense to me.
 
Hey guys i've got a question about powersupplies.

I tried to google it back but I didnt knew how to format the question,

The question is? what again was the sign that a psu was guranteed bad by the voltage distribution.

if the psu is rated 500w, and it has got 35A and 450w on the 12v rail, it was guranteed bad IIRC.
it was something with the 12v rail with a combination with wattage and Amps, can someone help me?
 
A modern PSU should have almost all of its rated wattage available on +12V (it may be 99%-100% on a Good one). The +5VSB should also not count against that total, although it's a piddling amount anyway; it is typically provided by a PSU-within-the-PSU.
 
Near 100% power of the 12V rail as the PSUs max is an indication the power supply uses DC-DC converters on the secondary side, as opposed to group regulation.
In group regulation, the 5V and 12V rail are regulated together, which has difficulties when the loads are imbalanced, such as in many modern power supplies. Loose crossload voltages is usually evident in group regulated power supplies.
 
I don't think he was asking, in any way, about group regulated versus DC-DC. He was specifically asking about knowing whether a PSU was a poor or incapable model based on the unit's labeled information. There are certainly DC-DC units that are not good examples of what a power supply should be that employ DC-DC but could never in any meaningful way sustain or even supply the total rated capacity or use creative math to arrive at some automagical total capacity.

Every power supply question doesn't need a primer on the differences between group regulation and DC-DC conversion. If it's relevant, fine, but often it's not. Please at least attempt to recognize the difference. I'm not sure what more we can offer you in the way of guidance and instruction in the need for you to do this. Continuing on this path is not going to end well and you've been made aware of this from a variety of users and moderators. Maybe find some other aspect to pick on?
 
Seriously, what is wrong with you? Moderators just mask comments they see with my name and "group regulated" or "s12ii" into some insult, argument, or whatever...

Obviously you mis-understood the context.
The only thing in the power delivery table that could give a hint to the quality, is the 12V power rating. Because generally PSUs with DC-DC converters have near 100% of their power on the 12V rail. There is no other aspect to pick on...
Not to say all DC-DC power supplies are 100% 12V rail, or that they're all even good. PSUs could even have fake labels.
Though the DC-DC converters do usually deliver tighter voltages on crossload, as opposed to the obselete group regulation design.

But you shouldn't judge a PSU by it's cover, as always, read reviews.
If a 500W has just 450w on the 12V rail, it's not guaranteed bad, it's just likely it won't perform well in crossload, or modern systems.

 
what again was the sign that a psu was guranteed bad by the voltage distribution.
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I don't think there is any really set method. One thing to look for that hasn't been mentioned is that stupid switch. If the PSU you are looking at has that voltage select switch, it's based on an ANCIENT design and should be passed on. We have moved on from that tech and I'm not aware of any PSUs that have that switch that are good buys in today's world.

The other indication is super strong minor rails. 25A on the 3.3 and the 5V rails used to be common. Not so much anymore. (Though I just looked and it's more common than I knew. 30A? I'm not sure.) But as mentioned above just seeing these doesn't mean it's bad, it just means old.
 
I believe what he is looking for, and it seems everybody has skipped right over it although I was fairly certain somebody would offer it so I didn't, is when a power supply says it is 500w on the box or on the top of the specifications label, or in the marketing descriptions, but when you calculate the actual wattage based on the specifications labels rated amperage, it does not equal or in many cases even come close to that figure.

For example, there are a bunch of units out there that say they are 500w, 600w, whatever, but when you calculate the actual formula you end up with more like 400w, 450w, 375w, whatever. Something other than, and significantly lower than, the marketed wattage. And when this IS the case, we usually find those units cannot even sustain the wattage you calculated, more like peak than continuous. Those are bad units and seeing this kind of discrepancy on the label generally indicates that you're dealing with a crappy power supply and probably a crappy manufacturer, although in the past I've seen this on some rather well known name brand units as well.

The number of watts is equal to amps multiplied by volts. That's it! In other words, watt=amp X volt. Sometimes you will see this formula written as W=A X V. [1]
For example, if the current is 3 amps (3A) and the voltage is 110V, you multiply 3 by 110, to get 330W (watts). The formula is P=3A X 110V = 330 W (with P standing for power).
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This of course does not necessarily take into account the differences between units that might use multiple weaker rails, single stronger rails or some few other factors that may be relevant in some cases as well.
 


Was looking at the thread over on Jonny Guru about the EVGA 450 BT and it's a train wreak PSU.

I wouldn't put that thing in any system.


Jonny Guru actually posted something about possible dumpster fire.
 
As a general rule I try to link our reviews first. We are on this site so it implies that we trust the editorial staff and product reviews. (I've been a mod long enough to know this isn't 100%.) I wasn't trying to bash the BT450 at all. I made the points I wanted made. I'm moving on now.
 


Yeah, I understand.

The issue is nobody else has reviewed it, some are currently in process however and it's not doing well from what I saw.

They have 2, at least one blew already.
 
You can add EVGA to that. All of the EVGA B3 units except the 650w model blew chunks when tested on Aris bench. Prior to that, it seems I recall the N1 and W1 units either failing testing or efficiency, can't remember exactly on that one.
 

That's a very nice build. Clean and well done.
 

Thank you. I appreciate that. :)

Since the time i took that above pic, i've put some more dedication into my PCs. Two latest pics as well if you haven't seen them already:
Skylake build before and after.
iRFRyM7.jpg

Haswell build before and after.
uncNr0G.jpg
 
Got a EVGA G2 750W coming next week, got it in a promotion buying the EVGA GTX 1080Ti FTW3, was part of the deal.

Not sure what I am going to do with it though, already using 2x Seasonic Prime Ti's and a Seasonic X-Series in my 3 machines now.

Could be a nice backup unit or testing unit.
 
Just saw that Seasonic has updated their S12II series with S12II EVO lineup,
specs: https://seasonic.com/s12ii-evo

Any other word about S12II EVO series? Couldn't find a review of S12II-450 EVO unit. Also, warranty reduction from 5 years (S12II series) to 3 years (S12II EVO series) is a concern to me and i'm suspicious if S12II EVO series is really better than original S12II series.
 
I don't see anything anywhere either. I did PM Aris to see if he knew anything about these that he could share, but they are probably too new for anybody to have looked at yet. Dropping to a 3 year warranty does not bode well though. Something must have been cheaped out on in there somewhere.

 
After thorough look of the S12II EVO specs page, i saw that the fan bearing is downgraded to sleeve bearing. Original S12II series uses fluid-dynamic bearing fan. It doesn't look good for S12II EVO series.

Only "upgrade" i saw from specs page is that S12II EVO series has 2x new features over S12II series:
* Compatible with the latest Intel and AMD platforms
* Compatible with the latest operating systems

OS doesn't state nor care which PSU is powering the PC and that feature is a moot point. Though, as far as 2nd feature goes, only thing i can think of is that Seasonic made S12II EVO series compatible with C6/C7 sleep states. But without review, i can't confirm that.

On the specs page, there is also stated:"This model is available in selected countries only."
I wonder, to whom that PSU was made? If for Asian/African market then the downgrade from S12II series would make a bit more sense.
 
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