PSU Fundamentals & Recommendations

seangoesbonk · **Posted:** Sun Apr 17, 2005 11:28 am

zepper wrote:

The proper method of calculating Power Factor is: PF=Cosine of the phase shift between the Voltage and Current wave forms in degrees.

From the article, "Mathematically, Power Factor (PF) is equal to Real Power divided by Apparent Power."

Mike says, PF = W/VA

You say, PF = cos(angle between W and VA) = cos(arccos(W/VA)) = W/ VA

Exact same thing.

zepper · **Posted:** Sun Apr 17, 2005 12:32 pm

Of course, to use my method one would have to use an O-scope - so the result must somehow be better, right...

.

.bh.

seangoesbonk · **Posted:** Sun Apr 17, 2005 12:47 pm

zepper wrote:

Of course, to use my method one would have to use an O-scope - so the result must somehow be better, right...

.

.bh.

Right. Then you can justify buying a scope!

I think the W/VA explanation is easier to understand for people who don't have an electrical background. As well, you can measure it with a simple (and relatively inexpensive) power meter.

tabbal · **Joined:** Thu Mar 17, 2005 11:23 am **Posts:** 39

MikeC wrote:

As promised in the thrread SPCR Ratings, the PSU numeric ranking system has been revised, and each and every PSU on the list has been assigned new values in the context of the new system.
http://www.silentpcreview.com/article28-page6.html

Mike,
I hope you are guessing right about :
"Seasonic S12-330, S12-380 (SS-330HB, SS-380HB Active PFC) 7+? 8?

Because I just ordered one!... just kidding!
I am pretty sure it will be a top premium PSU.

Lou Sid · **Joined:** Sun May 22, 2005 7:34 am **Posts:** 13

Anyone got a model number for the recommended Enermax Noisetaker 325 Active PFC? I have yet to find a Enermax 325W PSU here in Australia and its even harder without a model number. Seasonics just do not exist in Australia (AFAIK).

Lou Sid · **Joined:** Sun May 22, 2005 7:34 am **Posts:** 13

Is it this one? EG325AX-VE from

http://www.enermax.com.tw/products_page ... 18&Gid2=46

If so, that's annoying, as the only Noisetaker AX series PSU available in Australia is the big meaty 600W one. Anyone know anything about these Coolergiant VHB AX Series

http://www.enermax.com.tw/products_page ... 18&Gid2=46

They have three fans in them!!!

frankgehry · **Posted:** Tue Jul 19, 2005 7:43 pm

LS,

The noisetaker 325 review is out of date. The noisetaker 600 review is more recent and has a current model number. If you want the latest pick one from the link in your last post. There have been some refinements in the later models. - FG

The coolergiants are supposed to be somewhat noisier, and the blower is of questionable value.

gbaustin · **Joined:** Mon Jul 18, 2005 8:57 am **Posts:** 7

I found it astonishing that a power hungry system running flat out was only drawing 180 watts as the SPCR test system did. Talking to my brother about this, he brought up an observation. He mentioned that the test systems were all hooked up to a regulated source of power. He wonders what affect that has versus a real world situation where there are all sorts of fluctuation, from the incoming power to things like the A/C going on and off. He believes that a real world situation would result in a greater power requirement.
Any thoughts?

By the way, I'm in the process of gathering the components for my next system. Just got a Seasonic SS-500HT Rev. A2 from Buy.com. Only $113.73 (120.99 - 6% off coupon). Probably don't need half this power but I liked the positive things said about it at this site.

MikeC · **Posted:** Fri Jul 29, 2005 2:42 pm

Regulated power source? No such thing. Where did he get that idea? It was plug into the wall through the Seasonic Power Angel AC power meter, which does nothing but monitor the AC power.

gbaustin · **Joined:** Mon Jul 18, 2005 8:57 am **Posts:** 7

I quess it was the photos of all that impressive equipment.
Thanks for clarifying that.

Magnus_CA · **Joined:** Wed Aug 10, 2005 9:59 am **Posts:** 10

Hi All,

I stumbled across silentPCreview while searching for a power supply for my socket 939 nF4 ultra board. Thanks to Mike C's review of the Sea Sonic PSU's, I just ordered an S12-430. Prior to that I never paid much attention to fan noise nor did I ever care (or know about) efficiency. I'm sure there's plenty others out there like me who generally put a minimal amount of effort into researching PSU's and would really benefit from reading this site. So thanks Mike!

In addition to thanking Mike C for his reviews I wanted to propose a possible PSU review candidate:

COOLMAX "SLI" CXI-600B ATX v2.01 600W Power Supply

http://www.coolmaxusa.com/productDetail ... ory=single

Like the S12, it employs a single 120 mm fan on its belly. Considering the growing popularity of SLI it would be nice to find out if this PSU can handle the load and still get the silentpcreview seal of approval.

MikeC · **Posted:** Wed Aug 10, 2005 5:01 pm

Magnus_CA wrote:

In addition to thanking Mike C for his reviews I wanted to propose a possible PSU review candidate:

COOLMAX "SLI" CXI-600B ATX v2.01 600W Power Supply

http://www.coolmaxusa.com/productDetail ... ory=single

You're welcome Magnus.

The Coolmax PSU line you refer to appear to be revamped versions of the 600 watter we reviewed very recently... http://www.silentpcreview.com/article257-page1.html They're coming quite late to the ATX12V v2.xx spec, which has been out for almost 1.5 years. They know us and we know them; they'll send samples when they're ready.

MikeC · **Posted:** Thu Sep 08, 2005 8:52 am

Another Major Update Sept 8, 2005 - Revisions in selected portions of the text, update version info on PSU design guides, added info on 12V reliance, dual 12V lines, more system power examples, added new models and retired some old ones.

Slick · **Joined:** Sat Sep 10, 2005 10:32 am **Posts:** 5

Mike, on page 3 of the latest revision, it has

Quote:

Note that 12V2 only supplies the AUX12V (2x12V) 4-pin plug, which feeds only the CPU.

I know by fact (tech support & manual) Enermax's latest 2.0 PSUs, at least in the higher wattage range, shares the 12V2 line with the 20/24-pin connector. And according to this, HEC employs a AUX12V & PCI Express setup on the 12V2 line.

MikeC · **Posted:** Sat Sep 10, 2005 11:44 am

Slick wrote:

I know by fact (tech support & manual) Enermax's latest 2.0 PSUs, at least in the higher wattage range, shares the 12V2 line with the 20/24-pin connector. And according to this, HEC employs a AUX12V & PCI Express setup on the 12V2 line.

This is news to me. I just checked through the manuals for Enermax ATX12V v2 PSUs and cannot find any indication of 12V2 on the 24 pin line. Nor was there any reference about where the PCIe 6-pin connector gets its juice. Can you clarify your sources? It's also not clear where extremeoverclocking got that info about the different PSU connectors/lines.

Devonavar · **Posted:** Sat Sep 10, 2005 11:52 am

Perhaps it would be a good idea to revise that passage to point out that the ATX12V specs say that the AUX12V should be the only connector fed by +12V2. I get the feeling that this part of the ATX12V specs is not especially well followed.

Also, are you sure that it actually shares the rail with the AUX12V? Enermax may just be labelling the lines wrong (i.e., ATX12V, PCI12V and IDE12V may come from "+12V2", and the AUX12V may be on "+12V1"). There's no shortage of confusion about which connector comes from which header, the "CPU on +12V2" just comes from the ATX12V specs; not all manufacturers follow this labelling convention.

Slick · **Joined:** Sat Sep 10, 2005 10:32 am **Posts:** 5

That's what I thought at first. Actually the reason I contacted Enermax tech support which they then later confirmed with what the manual had listed. Also in the manual, the configuration between Enermax's high wattage models differs from the configuration of their lower wattage models (same page, 2 seperate diagrams). By that, one could assume it infers that there is indeed different 12V line configurations within Enermax's PSUs or that it could mean that the 2 seperate diagrams listed exist to indicate the presence of the PCI Express connector, however 12V2 is listed for both 20/24-pin connector & CPU on the higher wattage models (more SLI friendly/less CPU friendly in this regard) whereas 12V2 is listed for the 20/24-pin connector while the CPU is listed on 12V.

Slick · **Joined:** Sat Sep 10, 2005 10:32 am **Posts:** 5

MikeC wrote:

Slick wrote:

I know by fact (tech support & manual) Enermax's latest 2.0 PSUs, at least in the higher wattage range, shares the 12V2 line with the 20/24-pin connector. And according to this, HEC employs a AUX12V & PCI Express setup on the 12V2 line.

This is news to me. I just checked through the manuals for Enermax ATX12V v2 PSUs and cannot find any indication of 12V2 on the 24 pin line. Nor was there any reference about where the PCIe 6-pin connector gets its juice. Can you clarify your sources? It's also not clear where extremeoverclocking got that info about the different PSU connectors/lines.

My manual (Noisetaker) says 12V1 for the PCI Express connector & 12V2 for the 20/24-pin connector.

Slick · **Joined:** Sat Sep 10, 2005 10:32 am **Posts:** 5

I would also like to bring up this statement to attention (also on page 3

)

Quote:

12V1 supplies 12V to all the other components that require it. This can lead to a problem with high power gaming systems that utilize two high power video cards in SLI or Crossfire mode.

This statement might be a bit misleading in that it infers all PSUs (2 12V lines) with such a configuration could cause problems with SLI or similar system setups (Antec's 2.0s follows the 12V2 powers CPU only configuration I believe and is SLI certified), yet alot of PSUs on nVidia's SLI certified list have two 12V lines.

Perhaps clarification needs to be added in this instance?

Devonavar · **Posted:** Sat Sep 10, 2005 2:18 pm

Slick wrote:

I would also like to bring up this statement to attention (also on page 3

)

Quote:

12V1 supplies 12V to all the other components that require it. This can lead to a problem with high power gaming systems that utilize two high power video cards in SLI or Crossfire mode.

This statement might be a bit misleading in that it infers all PSUs (2 12V lines) with such a configuration could cause problems with SLI or similar system setups (Antec's 2.0s follows the 12V2 powers CPU only configuration I believe and is SLI certified), yet alot of PSUs on nVidia's SLI certified list have two 12V lines.

Perhaps clarification needs to be added in this instance?

Your "clarification" makes no sense to me. I agree, it does imply <semantic note: The proper word is imply, not infer. I infer a conclusion from what is implied, not the other way around.</semantics> that PSUs that place all SLI load on the +12V1 line could have problems. This is in fact the case (at least in PSUs that follow ATX12V 2.x, which is really all we can say) — if the SLI load somehow manages to rise above 240VA, it becomes a safety hazard. Note that it is very difficult to draw this kind of power. This is true whether or not a PSU is certified. I will admit up front that I don't know what nVidia does for certification testing, but I don't think it's relevant. Certification testing cannot guarantee that SLI will work because SLI isn't the only load on the system; the load on the +12V lines is determined by the system as a whole. If you happen to draw a lot of power from the +12V1 line — wherever the power is needed and how it is split up — you risk overloading the line.

That said, the actual possibility of problems from this configuration is extremely low as long as the PSU is rated honestly. I can only guess at the kind of system that would actually gobble 20A from a single line.

Slick · **Joined:** Sat Sep 10, 2005 10:32 am **Posts:** 5

Perhaps I'm reading too much into it & that "high power gaming systems" is relative when comparing different types of systems.

Quote:

Note that 12V2 only supplies the AUX12V (2x12V) 4-pin plug, which feeds only the CPU. 12V1 supplies 12V to all the other components that require it. This can lead to a problem with high power gaming systems that utilize two high power video cards in SLI or Crossfire mode.

Personally, I get the impression this says it's likely to be a problem, almost to the point that it will happen. In a way it's pretty much saying to me, Antec's SLI certified PSU is likely to fail in the type of setup it's certified for.

Now what I mean by clarification is perhaps the word "can" can be substituted with the word "might" or something of that nature. And that the word "can" makes it out to be a bit misleading.

Truth be told, I haven't heard many or if at all any power lacking related stories between SLI certified PSUs w/ two 12V lines & systems built around SLI or similar to suggest a high likelihood to failure. At least for the present time being.

Perhaps I'm asking too much and if so, then I apologize for suggesting to make a very detailed and informative PSU article a bit clearer.

Devonavar · **Posted:** Sun Sep 11, 2005 4:30 pm

I'd say that changing "can" to "might" is probably a good change. We certainly don't mean to imply that a dual line PSU will have problems — that's simply not correct.

MikeC · **Posted:** Sun Sep 11, 2005 6:00 pm

OK, the section at the bottom of page 3 that's so hotly debated here has been changed:

Quote:

Note that 12V2 only supplies the AUX12V (2x12V) 4-pin plug, which feeds only the CPU. With PSUs that adhere to the ATX 12V v2.xx Guide, 12V1 supplies 12V to all the other components that require it. This might lead to a problem with very high power gaming systems that utilize two high power video cards in SLI or Crossfire mode. Current high end VGA cards by themselves can draw >90VA each. Much of this comes from the 12V line via the 6-pin PCIe connector for the VGA card. If you add several hard drives and optical drives, the 240VA limit may be too low.

The current ATX12V v2.2 spec was created before dual VGA card gaming configurations for Intel boards were announced. SLI, being an AMD feature that came many months before, may have been ignored by Intel's PSU design guide team. We can anticipate an adjustment in the ATX12V spec to better serve the needs of high end gamers. There is talk of doing away with the 240VA limit (20A @ 12V) or specifying three 12V lines .

Not all PSUs with dual 12V lines and two 6-pin PCIe connectors follow ATX12V v2.xx to the letter, however, especially as the guide does not cover the 6-pin 12V PCIe outputs. This connector was specified by nVidia, the originator of the SLI concept. There is evidence to suggest that some PSU makers are using 12V2 to supply more than just the 2x12V or 4x12V connectors. More information on this topic will be provided after it is verified.

PositiveSpin · **Joined:** Sat Jul 24, 2004 5:03 am **Posts:** 137

I liked the explanation of power ratings vs temperature, and how a hot PSU may not deliver its rated output.

Then I noticed that PC Power and Coolings ratings (on their website) specify their rated output at 50 degrees C.

Now I appreciate the significance of that annotation (and I'm more impressed with their products).

Thanks.

ATWindsor · **Joined:** Mon Apr 18, 2005 11:53 pm **Posts:** 284

seangoesbonk wrote:

zepper wrote:

The proper method of calculating Power Factor is: PF=Cosine of the phase shift between the Voltage and Current wave forms in degrees.

From the article, "Mathematically, Power Factor (PF) is equal to Real Power divided by Apparent Power."

Mike says, PF = W/VA

Actually, thats not quite what he says, VA and W is only units, "real power" and "apparant power" is a size (or whatever the correct term is in english). W and VA are the exact same unit, and are exectly the same and interchanable, real power and apparant power is not always the same (or rarly the same if you want).

AtW

winguy · **Joined:** Tue Nov 02, 2004 9:31 am **Posts:** 447

Currently which PSUs are AXT12V v2.2 certified/compliant?

MikeC · **Posted:** Sun Sep 18, 2005 8:17 am

winguy wrote:

Currently which PSUs are AXT12V v2.2 certified/compliant?

See the link to Intel's list in this post: Confused about Dual 12V lines? Here's the FAQ!

cfrankb · **Joined:** Wed Oct 05, 2005 11:36 am **Posts:** 1

The Antec NeoHE product line (not the older NeoPower 480) have three +12V output circuits. The Antec TruePower 2.0 product line (as opposed to the SmartPower line) have 120mm fans and "dedicated output for more stability and less ripple noise"...something about separating the 3.3, 5, and 12V loads? Can someone comment on these features/benefits, especially the last one?
Thanks,
Frank

shanizar · **Joined:** Tue Oct 18, 2005 12:12 pm **Posts:** 57

Hi!
Great recommendations! I'm building a system and have been recommended this power supply: FSP350-60THN-P (or the 300W version)

Have you tested it and not found it good enough for the recommended list, or isn't it tested?

MikeC · **Posted:** Wed Oct 19, 2005 7:03 am

shanizar wrote:

Hi!
Great recommendations! I'm building a system and have been recommended this power supply: FSP350-60THN-P (or the 300W version)

Have you tested it and not found it good enough for the recommended list, or isn't it tested?

There are hundreds of PSU models out there. We can't test them all. But I've yet to see to fan-cooled PSU from Fortron quiet enough to satisfy me (or most hardcore silencers aroudn here). Their fan controllers and fans just aren't good enough. Only the Zen among the Fortrons is worth considering unmodded, for me.

There are other fan-cooled models we have tested & do recommend. I suggest you seek one of them out if you're wanting a "safe" quiet purchase.

PSU Fundamentals & Recommendations

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