Why is the PSU often under estimated?

[EJSLP]

I was researching the web to try to learn about PC's and their components and came across something about how a PSU is probably the most important thing to
choose in your PC.
it went on to say most dont give the psu much thought and just buy anything that seems like a bargin?
I would think it is a good idea to get something at least gold rated?
i went with platinum but was wondering what determines how good a PSU really is?

 

[Z15CAM]

what determines how good a PSU really is?

Suggest you look into reading PSU Reviews from these Respectable Sites:
http://www.hardwaresecrets.com/

http://www.jonnyguru.com/

http://www.guru3d.com/

 

[zir_blazer]

Actually, they are simultaneously both the most often underestimated AND the most overestimated too. You will figure that out yourself when you see a whooping 600W+ Power Supplies in many builds that would be better serve by a cheaper, lower capacity Power Supply as well because the actual power consumption of your typical mainstream build doesn't even scratch 300W.
What matters is that the Power Supply is of a good build quality and reliable, and that you have a decent knowledge of your actual power consumption needs. Most does not and thus goes on an overkill spree because they think that they need big, expensive Power Supplies, having absolutely no knowledge of the true real power consumption.

 

[EJSLP]

Actually, they are simultaneously both the most often underestimated AND the most overestimated too. You will figure that out yourself when you see a whooping 600W+ Power Supplies in many builds that would be better serve by a cheaper, lower capacity Power Supply as well because the actual power consumption of your typical mainstream build doesn't even scratch 300W.
What matters is that the Power Supply is of a good build quality and reliable, and that you have a decent knowledge of your actual power consumption needs. Most does not and thus goes on an overkill spree because they think that they need big, expensive Power Supplies, having absolutely no knowledge of the true real power consumption.

well me being a complete NOOB at this you just described me!
I have NO idea of what makes one better than another?
I see guys saying the gold rated is better than platinum and some bronze better than gold and platinum?
thats why i posted this, it seems there really is not a straightforward and definite answer?

 

[EJSLP]

Suggest you look into reading PSU Reviews from these Respectable Sites:
http://www.hardwaresecrets.com/

http://www.jonnyguru.com/

http://www.guru3d.com/

thanks but i thought that even if a product gets a great review thats really doesn't tell the whole story.
like if one of those sites rated a seasonic excellent and a guy buys one and it is DOA which i have seen on users reviews?

 

[EJSLP]

Actually, they are simultaneously both the most often underestimated AND the most overestimated too. You will figure that out yourself when you see a whooping 600W+ Power Supplies

Let's use a Evga GTX 780 i ordered for a example, They(evga) say too use a minimum of a 600 watt PSU? is this wrong? or is it just a recommended rating?

 

[Z15CAM]

Considering you have spend a bundle on a 780Ti I would not skimp on the PSU. I recommend this Seasonic KM3 designed 750W unit from XFX: http://www.hardwaresecrets.com/prin...Edition-Full-Modular-Power-Supply-Review/1695

And if you plan to SLI the 780Ti go for the KM3 BEFX XFX 850W Pro Black Edition although the XFX 750W BEFX Pro Black Edition would probably handle it.

 

[EJSLP]

Considering you have spend a bundle on a 780Ti I would not skimp on the PSU. I recommend this Seasonic KM3 designed 750W unit from XFX: http://www.hardwaresecrets.com/prin...Edition-Full-Modular-Power-Supply-Review/1695

And if you plan to SLI the 780Ti go for the KM3 BEFX XFX 850W Pro Black Edition.

Is that a much better choice than this one i already have on the way?
http://www.newegg.com/Product/Produc...&SID=u00000687
It is not a issue sending the seasonic back for exchange or refund if it is
Ps, my 780 is not a Ti just a reg GTX 770 super clocked by evga

 

[Z15CAM]

I do not know why you did not tell us what you have and plan on doing?

Both PSU's are Seasonic KM3 designs and both 80 PLUS PLATINUM. For $40 less the XFX unit with the same efficiency has 90 Watts more in reserve. That Seasonic SS-660XP2 will do just fine for a Single 780Ti. Both Seasonic and Corsair are over priced in my opinion. XFX doesn't make a 650 or 660W Seasonic KM3 Unit.

As far a Gold Vs Platinum efficiency; if both pass Platinum Efficiency Specs although one is specified as Gold, they are both Platinum - This is Marketing.

Things to consider when buying a PSU is the average Load your system places on the PSU compared to it being max'd or considering SLI or CF in the future. For instance; a 660W Platinum unit requires 89% efficiency at full load of 660W's with the Fan Buzzing to dissipate the Heat. Say your system requires an average of 400 Watts. That means the PSU is running at 60% load. The concern becomes how much does that PSU spin up in relation to heat and noise; where as, a 750W PSU is only operating at 53% and will generate less heat and be less noisy.

 

[Puffnstuff]

Well I get bashed here for having a 1kw ps in my system and it was enough when it worked right. Now that it's 4 years old it can no longer provide that output and if I run my system at my normal oc setting the power draw is now beyond what it can supply and my system will shut down. When I replace it I'm going up to at least 1.3kw so that I will have even more headroom. I've seen my system pull upwards of 900w from my apc while gaming so 100w of margin was slim to begin with. And one more thing, I'm going back to enermax ps's which have consistently been the best ps's I've ever used in my systems.

 

[Z15CAM]

Thanks Puff - Exactly what I am getting at.

 

[Torn Mind]

Because people only think that turning something on is the only thing to worry about when buying a PSU. It turns on, and then they go to Newegg and Amazon with a 5-star review essentially saying "It works!!!". Yes, even Diabloteks and Logisys units have their fair share of units that "work", but you can't see the poor ripple control or that the internals are simply inadequate to deliver the rated wattage, which leads in to the subsequent reason in this post.

Because the tools to analyze PSUs are not necessarily well-known to non-hobbyists. Multimeters are fairly affordable, but oscilloscopes and load testers cost more than a mid-to-high end computer. ESR meters go for $100, and sometimes you need a soldering iron too. Plus, opening up the unit voids the warranty, so even a basic visual inspection carries a "penalty" for the latest new units.

A little electrical theory is also required, and too much info can overwhelm someone who doesn't know about that stuff. Heck, I didn't know crap about PSUs in the fall of 2012, which when I "started" with my little obsession with computers and their parts.

And stuff like Japanese companies making better capacitors than others is something that had to be passed down from "those in the know" to the reviewers who then pass it down to end users, like me and everyone else.

 

[bgt]

The problem with most PSU's is the fact that the power indicated on the PSU is not the total power of the 12V rail. Thats why I use Seasonic(Platinium/Gold types). If it says 400W you can be sure the 12V output is almost 400W net. And that's what counts for GPU cards(+CPU's ofcourse).

 

[TemjinGold]

Err no. The power indicated is indeed the power the psu can output. A lower efficiency PSU will pull MORE from the wall to output it, not output less total.

 

[Blain]

Why is the PSU often under estimated?

I was researching the web to try to learn about PC's and their components and came across something about how a PSU is probably the most important thing to
choose in your PC.
it went on to say most dont give the psu much thought and just buy anything that seems like a bargin?
I would think it is a good idea to get something at least gold rated?
i went with platinum but was wondering what determines how good a PSU really is?

1. The Windows Experience testing doesn't have a score number for power supplies.
2. Metal status is a marketing ploy to generate sales.

 

[bgt]

Err no. The power indicated is indeed the power the psu can output.

A lot of PSU'd dont put their so called "indicated power" to a single 12V line. They put it to a combination. And thats why you have a difference in PSU's. Read the indication sticker carefully, you will see good PSU's having the indicated power all delivered to a single 12V line and other having less power to 12v lines and indicating a combined mode. Thats why a medium heavy GPU can run on f.i on a 400W Seasonic PSU and not on a cheap 400W PSU. I am not talking about efficiency here. Purely output power to a single 12V line.

 

[JEDIYoda]

Err no. The power indicated is indeed the power the psu can output. A lower efficiency PSU will pull MORE from the wall to output it, not output less total

a few pennies on the dollar..nothing to get concerned over...

 

[TemjinGold]

a few pennies on the dollar..nothing to get concerned over...

That wasn't put as a concern. I'm simply explaining what the other guy doesn't get.

 

[TemjinGold]

A lot of PSU'd dont put their so called "indicated power" to a single 12V line. They put it to a combination. And thats why you have a difference in PSU's. Read the indication sticker carefully, you will see good PSU's having the indicated power all delivered to a single 12V line and other having less power to 12v lines and indicating a combined mode. Thats why a medium heavy GPU can run on f.i on a 400W Seasonic PSU and not on a cheap 400W PSU. I am not talking about efficiency here. Purely output power to a single 12V line.

I think I misread your original post, my bad. I thought you meant that a 400w pulls 400 from the wall, so less efficiency means less power.

 

[bgt]

I think I misread your original post, my bad. I thought you meant that a 400w pulls 400 from the wall, so less efficiency means less power.

Thats why I like Seasonic type of power supplies.........all the energy goes to a single 12V line and from there to the 5 and 3.3V lines through a DC-DC converter. And i really like the Seasonic quality. I will Always advice them to people who can afford it. They are silent and robust.

 

[dave_the_nerd]

Let's use a Evga GTX 780 i ordered for a example, They(evga) say too use a minimum of a 600 watt PSU? is this wrong? or is it just a recommended rating?

GPU manufacturers overstate their PSU requirements because they don't know what quality PSU you are using, or what other components you have in your system.

There are two other problems: 1) a lot of (particularly cheap) PSUs don't actually output the wattage they're rated for. 2) All PSUs get "tired" as they age and are able to put out less overall.

An i3 rig and a GTX 780 with a single SSD, at stock voltages and speeds, will probably run on a 400w PSU no problem. But if I'm adding that same GPU to an aggressively overclocked, fully kitted out gaming rig, I could be using 600w of power before I even drop in the video card.

 

[lehtv]

Thats why I like Seasonic type of power supplies.........all the energy goes to a single 12V line and from there to the 5 and 3.3V lines through a DC-DC converter. And i really like the Seasonic quality. I will Always advice them to people who can afford it. They are silent and robust.

Some Seasonics still in production are group regulated though, i.e. they have separate rails for voltages. S12II 520W/620W for example

 

[AnonymouseUser]

Let's use a Evga GTX 780 i ordered for a example, They(evga) say too use a minimum of a 600 watt PSU? is this wrong? or is it just a recommended rating?

They are covering their bases, so to speak. Most people skimp on the PSU and buy a cheap 600W PSU that can truly only sustain ~400W max. The reality is that even 600W is overkill when using quality PSUs.

Here you can see what the GTX 780 uses at the wall in a system with an i7 4960x (high consumption CPU):

Though in this benchmark it’s worth pointing out that we’re measuring from the wall

The PSU being used is the Corsair AX1200i, an 80+ Platinum PSU that is ~89% efficient @ low load, which means actual consumption is 327 * 89% = ~290W (that's total system power consumption).

The main factor is the 12V rail, as cheap PSUs combine all rails for their total output wattage. High quality PSUs are usually rated at 12V output only for their total output.

For example, this cheap Diablotek 600W PSU is really only a 480W PSU, but may be OK in a basic sytem with the GTX 780:

Compared to the Seasonic 660W:

The reality is that even that 660W Seasonic is overkill for the GTX 780 unless you are using a lot of additional components in your system (hard drives, RAID cards, optical drives, etc).

 

[silicon]

I was researching the web to try to learn about PC's and their components and came across something about how a PSU is probably the most important thing to
choose in your PC.
it went on to say most dont give the psu much thought and just buy anything that seems like a bargin?
I would think it is a good idea to get something at least gold rated?
i went with platinum but was wondering what determines how good a PSU really is?

What determines a good PSU is the quality of the components, the electrical design, the load and line regulation, ripple on the output rails, its efficiency, modularity of the cables and so on. Cheap PSU's with cheap components will fail more often and with a high risk of killing the MB and other components. Always read the comments about the supply in question as user rating are important. A quality PSU will last a long time and maintain its specs over time while putting less risk for the MB and other.

 

[bgt]

Some Seasonics still in production are group regulated though, i.e. they have separate rails for voltages. S12II 520W/620W for example

I mean the Seasonic Platinium and Gold series. The G series have true 12V power also and are not so expensive and have 1 of the best low load efficiencies(75% at 22,5W),the 660W Platinium also(76% at 22,5W).