Are Rosewill's safe?

[370forlife]

I bought a rosewill stallion series RD500-2SB 500w psu about a year ago. Its still running good, all the voltages are steady, computer runs fine. Never had any problems with it with heat, its quiet, has blue led's, 120mm fan that sucks the air away from my ram.

But has anyone had any problems with one of these?

[dood]

Re: Are Rosewill's safe?

Haven't heard any problems. What caps are on it? Can you make out who manufactures it? Keep an eye out on the board inside for any manufacturer clues.

[PCBONEZ]

Re: Are Rosewill's safe?

Rosewill RX - Teapo
Rosewill Xtreme - Teapo
Rosewill RP Series - FUJHYUU - built by ATNG
I don't know about their others for sure but Newegg ratings (with significant numbers of reviews) lead me to steer clear of their other series'.

[Newbie2]

Re: Are Rosewill's safe?

Rosewill power supplies are not the best, but they aren't bad. They are better than any generic power supply you'll find.

[kc8adu]

Re: Are Rosewill's safe?

last rosewill i saw was a gutless wonder.

[PCBONEZ]

Re: Are Rosewill's safe?

Rosewill doesn't make PSU's they are an OEM.
They buy them from someone else and re-brand them.
Who that someone else is (and it's quality) depends on the specific model.

So, you can't really say: Is 'Rosewill' good or bad because each model is different.
You have to look into the specific model.
~
For the most part Rosewill goes with cheap builds from debatable builders.
That doesn't mean they have no good models but they certainly have many bad ones.

.

[Newbie2]

Re: Are Rosewill's safe?

Rosewill power supplies are seen by me as budget power supplies, they aren't that great in quality when you look at them, but the price isn't bad and very high either.

Rosewill power supplies are rebranded, depending on what you bought you will either get a decent power supply or a lightweight cheap power supply.

For example, if you get a cheap Rosewill power supply, you can save a good amount of money on a $20 power supply but quality will not be so great. Here's one example, and this one is made by the infamous Deer manufacturer (UL number E203196): http://www.newegg.com/Product/Produc...82E16817182023

Another example is if you buy a higher end Rosewill power supply. You will spend more money, but this time it will be made by the not-so-common ATNG manufacturer (UL number E186010). It should be able to run a standard mid-to-high end "gaming" computer. The link here: http://www.newegg.com/Product/Produc...82E16817182096


Also, here is a hardwaresecrets review of a Solytech-manufactured Rosewill power supply. Its noise on the +12V rails were somewhat high, but acceptable. The link to this review is here: http://www.hardwaresecrets.com/article/558/1

[zandrax]

Re: Are Rosewill's safe?

So Rosewill is like Thermaltake, an OEM which rebrands psus from different manifacturers and with different build quality.

@ 370forlife: I didn't found any serious review about the RD500-2SD: from Newegg specs page, it weights 5.2 lbs (2.35 kg) and has a voltage switch so it should employ a passive pfc; the label reporting a SL-8500BTX model name and the UL number E223918 brings to Solytech, maybe more known for Deer, L&C and Allied psus. Looking in the Solytech site, there isn't a SL-8500BTX, only a SL-8400BTX which has a similar look or a SL-8500EPS which, however, boast an Active PFC so it's a completely different product.
Given no clues from Solytech, I come back to Rosewill's label: first I spot usual Solytech tendence to overrate values, but only a bit (22 A at 3.3 V and 16 A at 5 V, combinated 130 W vs the sum of 152.6 W; 15 A and 16 A for both 12V rails but 480 W combinated power for 3.3, 5 and 12 : this means, if numbers matters and are true, a 350 W limit on 12 V rails which is plausible) then I notice the lack of any national electrical conformity logo (there is only FCC), as usual.
In short: this seems to be an ATX 2.x complaint design, but do not expect high efficiency due to passive pfc. IMHO it's more substantial than a cheap Deer gutless wonder (at least has a big coil for passive pfc: let's hope Solytech didn't spare too much on components), but it costs about $40 ($60 with a $20 discount): at $60-70 you can find decent units and now Newegg ships the Corsair VX450 ($70) with a $15 mail-in rebate. Given this rebate, is the Rosewill still a good bang for the buck?

Zandrax

[370forlife]

Re: Are Rosewill's safe?

"passive" pfc, does that mean it has no fan? No heatsinks in it? or what? Because that psu has a 120mm fan on the bottom with auto speed control, and you can see heatsinks inside of the psu.

[PCBONEZ]

Re: Are Rosewill's safe?

PFC = Power Factor Correction
Switch mode power supplies shift volts out of phase with amps (on the input).
[So does anything else that isn't a purely resistive load on AC.]

PF = Power Factor = the ratio of the real power to the apparent power.
Real power = the capacity of the circuit for performing work in a particular time.
[Real Watts -> Energy actually used]
Apparent power = the product of the current and voltage of the circuit.
[Apparent Watts -> Amps x Volts]
When volts and Amps are out of phase Apparent power is less than Real Power.

Real Power x PF = Apparent power
[PF is always less than 1 unless the load is purely resistive then it = 1]

PFC makes PF closer to one.
Passive / Active are different ways of implimenting PFC.
Active gets it closer to 1 that passive does.

What this does for you:
It costs you more to buy the PSU (more parts).
It costs you more on your electric bill (more parts so more heat lost to get the same amount of DC output)

What it does for the environment:
It uses more energy to do the same thing as would be done without it.
(more parts so more heat lost to get the same amount of DC output)

What this does for the power company:
They get to charge you more on your bill.
[This is why PFC is now law in many countries.]
Most Utility Companies meters measure Real Power

What this does for REAL PSU Efficiency: It makes it less. More heat is lost.

Apparent PSU Efficiency gos up.
- They use this to confuse consumers and sell them on the idea that PFC is good for them.
It's not good for consumers.
It's not good for the environment.
It's good for power companies. [And that's why it's law.]

.

[PCBONEZ]

Re: Are Rosewill's safe?

And as to your actual question. [Since I didn't actually say.]

PFC has nothing to do with the method of cooling.

.

[Newbie2]

Re: Are Rosewill's safe?

PFC changes the efficiency of a power supply, often to increase it and as a side effect it can lower your power bill.

Active PFC is better than passive PFC.

[PCBONEZ]

Re: Are Rosewill's safe?

Seems Newbie2 bought into the advertising hype.

It does NOT lower your power bill.
It Raises your power bill.
-
It was forced into law in the UK because many of the power companies are Gov't owned (which makes it easy to get it into law) and they want to collect on all that power that doesn't show up on the meter if you don't have PFC.

PSU makers don't want to make UK and non-UK versions so everyone gets PFC because it's the law in the UK.

It does NOT increase the efficiency of your power supply.
- The power out of it will be the same.
- The heat loses will be more.
- Less efficient.

It increases the efficiency OF YOUR ELECTRIC METER.
For the same power out of your PSU - your meter will read higher.

.

[Newbie2]

Re: Are Rosewill's safe?

So having the Antec Earthwatts EA380 380W ATX12V v2.2 active PFC power supply that is in my computer is actually a bad thing?

[PCBONEZ]

Re: Are Rosewill's safe?

No: It's fine:
But same PSU with no PFC would give the system the same power as now, lose less energy as heat, and show less on your power bill if your meter works the same as those in the UK. (Most of US uses a different meter than UK. I dunno about Canada.)
.
I just hate that manufacturers pass off PFC as having some big benefit to end users so that they can charge more for something required by law anyway.
- To the user there is no advantage with PFC.
.

[zandrax]

Re: Are Rosewill's safe?

@ Newbie2: no, your Antec is a good psu and PCBONEZ is right about pfc.
I explained it wrong: pfc means power factor correction which is different from efficiency.

Imagine a horse towing a train wagon: if the horse walks following the wagon axis, then all its energy is spent to move the wagon; if the horse walks sideways the wagon, it is unable to move the vehicle; if the horse is in an intermediate position, then some energy is used to move the wagon and some is not. Call active power the energy used to move the vehicle during a period of time and reactive power the energy spent without moving during the same period: the vectorial sum of active and reactive power is called apparent power; graphically, apparent power is the hypotenuse of a right triangle having active and reactive power as catheti.



The angle between active and apparent power is called phi (the Greek lowercase letter should be φ) and the ratio between active and apparent power is called cos(φ) or power factor (pf): when power factor is 1, φ is 0 then apparent power equals active power and your device is drawing exactly the energy it needs; when pf is very low, φ is near 90 degrees and the device draws a lot of reactive power, way more than the active one. An interesting example is a pf of 0.7: this means the active power is 0,7 times the apparent power or, in other words, the apparent power is 1,41 times the active one. 1.41 is roughly the square root of 2 and 2 is 1 (active power) + 1 (reactive one): the device draws active power as much as reactive one.
Reactive power is power that your electrical device draws, don't use for its work and throw back into the main power line: however power plants have to erogate the energy "wasted" in reactive power and power lines have to transport it, so reducing the reactive power helps in reducing the load on power plants and lines. This is the main advantage, for electricity companies and for the environment (less energy "wasted" -> less energy produced, so less pollution from gas/oil power plants): there is little or no direct advantage for Average Joe, since most electricity companies charge active power for house lines (but both active and reactive for industrial ones: no wonder factories use pf correctors from ages), but environment should thank you anyway.

Efficiency, OTOH, is completely different from pfc: all devices transfer part of active power into their work, while a (hopefully) smaller part is turned into heat. Efficiency is the ratio between the energy of the active power used for work and the energy of the active itself and it's always inferior to 1 because heat is a consequence of energy transformation (Kelvin statement of 2nd law of thermodynamics): our goal is to come as closer as possible to 1, so boasting an high efficiency and turn into heat the smallest part of energy. In this case benefits are for everyone: you pay all energy you consume and everything that allows a better use of energy helps reducing you electricity bill both directly and indirectly (less heat -> reduced cooling). Physics would say this helps in a very very small extent in reducing the enthropy of the universe because stars don't follow regulations about efficiency and are massive producers of enthropy, but I don't want to lose the audience now

Lesson stops here , but you can read the pamphlet from which I took the horse example and the image, if you like.

Back to power supplies, the correlation between pfc and efficiency is a simple rule of thumb: while in theory every psu design can work with an active, a passive or no pfc, in practice usually older psu designs (those dated back to the 200W AT psu) are "retrofitted" with a cheap passive pfc (which is a choke coil most of times) and active pfc is deeply integrated into more modern designs to enhance performances and make efficiency higher. In fact, nowadays power supplies are designed around a combo pfc/pwm controller such as the ubiquitos Champion Micro CM6800, which controls both pfc and the switching frequency of main transformer; switching frequency pays a great role for efficiency, usually the higher the frequency the higher the efficiency.
Claims that psus with active pfc have a lower efficiency than pfc-less ones can be true only if all psus share the same design because the active pfc circuitry uses a bit of power and heats a bit too; anyway I don't know if such products do exist and I wonder if the amount of power used for the active pfc circuit is comparable to reactive power not required from power plants. I suspect the additional power draw is inferior to the reactive a pfc-less draws, I wish I had some evidence supporting it.

Zandrax

[PCBONEZ]

Re: Are Rosewill's safe?

Zandrax has it exactly.
-
Restating part:
PFC ends up in more advanced PSU's designs that happen to be more efficient than older designs FOR OTHER REASONS than the PFC.
-
If the exactly same PSU design was used for two PSU's: except one has PFC and the other does not: the one without PFC would be MORE efficient because with fewer parts there would be less heat lost inside the PSU.

~~~
An electric motor is another device that has a power factor. (Like a SMPS)
If you take two identical motors with identical loads on the output (mechanical)
.. then add extra circuits to only one of them (for PFC).
.. which 'motor system' will lose more heat overall?
No PFC -> Heat losses of motor.
PFC -> Same heat losses of motor + heat losses of PFC components.

Now does it make sense?

.

[RJARRRPCGP]

Re: Are Rosewill's safe?

Are you trying to say that my 500W PSU will force 500W of draw all the time, even with 1 percent of processor usage?

Now you're making me feel bad about getting my Fortron 500W PSU.

[zandrax]

Re: Are Rosewill's safe?

Are you trying to say that my 500W PSU will force 500W of draw all the time, even with 1 percent of processor usage?

Nobody wrote that: the psu doesn't draw a fixed amount of power but one depending on what components require. The relationship between power erogated to components and power drawn from mains is called efficiency and usually it's not constant but varies according to load and follows a so-called bell curve in a power drawn vs efficiency graph.
As a rule of thumb, efficiency is low at very low (less than 10% of rated power) and very high loads (above 85-90%) and reaches the peak in the mid load. The bell curve is likely to resemble more old psus than newer models: there are a lot of exceptions (the following psu is more efficient at mid-low loads than at high ones and the curve barely resembles a bell) now that regulations and the 80plus certification require a minimal efficiency at various loads.



For example, in idle an average computer (dual core, mid level graphic card, one hard disk, one dvd-rw) requires roughly 80 W; in order to erogate 80 W, the above psu (rated 550 W) draws some watts more: with 76% efficiency in the 100 W range, it draws exactly 80 / 0.76 = 105 W (plus reactive power if pfc is less than 1, but this is another story) and not 550

Zandrax

Image from PSU article at motherboards.org.

[Gianni]

Re: Are Rosewill's safe?

efficiency is low at very low (less than 10% of rated power) and very high loads (above 85-90%)

That's correct: the wasted power is some componets/parts is the same at any output power so it is obvious that at light load you have a poor efficiency.
The maximum efficiency depends on the design, I have seen some ATX PSU reviews that show an efficiency very high at low~half load.
From my experience on industrial PSU I have seen that you have the best efficiency with a load ranging from 75% to 85% of maximum load.
Since the computer is not a fixed load and I think it is better to have a PSU with good efficiency at low~half nominal power.

Gianni