psu suggestions for q6000 and 8800 gts

[John]

Originally posted by: dclive

Originally posted by: mxnerd
Do you have bad experience with 80+ certified that gone bad? Can you be more specific which brand and model?

My understanding is the new 80+ rating is just a (new marketing-oriented) mathematical model that says it passes X amount of energy when you put Y amount of energy into the plug.

It has no necessary relationship with quality.

The fact of the matter is that most 80 plus certed psu's are high quality units.

 

[mxnerd]

http://www.80plus.org/80what.htm

What is the 80 PLUS specification?

The 80 PLUS performance specification requires power supplies in computers and servers to be 80% or greater energy efficient at 20%, 50% and 100% of rated load with a true power factor of 0.9 or greater

If you don't have better design & higher quality, how do you pass the certification?

I defenitely know even when a manufacturer have some models passed the certification, that doesn't mean the quality are equal between different manufactures and models, but it does pass the minimum standard, isn't it?

I'm not expert, unless someone tell me which brand is best and which brand is worst, even if they passed the certification.

 

[dclive]

That's a *design* issue, not a *quality* issue. Quality can mean a lot of things, but the 80+ spec only means what you wrote.

Quality to me means something that will do what it says (a certain specification), in a repeatable way (consistent), for a long length of the time (at least the lifetime of the machine in question - perhaps 3-4 years).

 

[dclive]

Can anyone define this:
"with a true power factor of 0.9 or greater"

for me?

 

[BoomerD]

http://www.allaboutcircuits.com/vol_2/chpt_11/2.html

it's all greek to me, but it may make sense to some of you...

 

[mxnerd]

That's why I said I'm not expert. I don't know which brand use better quality components which will last longer in a consistent way. Do you have a top to bottom list?

 

[dclive]

Can we get anyone with an engineering background (i.e. not a PSU marketing site) to say why we'd care about .9 TPF vs. .8 TPF, or .1 TPF, for that matter?

 

[BoomerD]

Since JonnyGuru's site seems to stlill be down...
Some of these are a bit dated and don't include the newest models, but...

http://www.xtremesystems.org/f...howthread.php?t=108088

http://www.overclock.net/power...ed-power-supplies.html

and of course:
http://www.hardforum.com/showthread.php?t=844691

 

[SerpentRoyal]

Originally posted by: dclive
Can we get anyone with an engineering background (i.e. not a PSU marketing site) to say why we'd care about .9 TPF vs. .8 TPF, or .1 TPF, for that matter?

Even EE folks have a hard time explaining this stuff. An electronic circuit is often a combination of resistors, capacitors, and inductors.

The right angle triangle at the bottom of that link gives a good graphical depiction of the whole thing. Combining True power (often associated with resistors) and Reactive power (often associated with capacitors and inductors) will result in Apparent power (volt x amps).

I believe the majority of popular watts meter display APPARENT POWER. Note that apparent power is always greater than or equal to true power plus reactive power.

Power factor = True power/Apparent power. In a circuit with only resistors, the power factor is one (true power = apparent power). In a circuit with only capacitors OR inductors, the power factor is zero.

Let's get back to that power triangle. If the power factor is under one, then we know that there will be a reactive power component in the circuit. The reactive power requires additional current to deliver the same amount of true power.

US homes are not subjected to a tax penalty if the power factor falls below unity. Therefore, your electricity bill will be the same with two PSUs having identical efficiency curve, even if one has 0.99PF and the other with 0.6PF.

 

[mxnerd]

Originally posted by: BoomerD
Since JonnyGuru's site seems to stlill be down...
Some of these are a bit dated and don't include the newest models, but...

http://www.xtremesystems.org/f...howthread.php?t=108088

http://www.overclock.net/power...ed-power-supplies.html

and of course:
http://www.hardforum.com/showthread.php?t=844691

Thanks for the links.

In the forum I saw people saying bare minimum 300W is enough. But even with 80% efficiency, the output will be 240W max, and a lot of PSU is not 80% efficient, let's say it's 70%, then it's 210W under normal use. If under load the effeciency could be even lower.

So if you have a power hungry graphics card & CPU, 4 hard disks, plus some add-in cards like RAID, Gigabit NIC, TV tuner, several cooling fans, then you are approaching the limit or could be over.

What I don't understand is, if you don't stress your car at 120MPH for 8 hours a day just because it's rated for 150MPH, why would you settle for bare minimum for PSU and risk the stability of the system? I have been there, done that, and regretted it.

Unless you know definitely you will not upgrade your rig in the future. And most uses do! So why don't give it a little head room? I'm not suggesting 600W, though.

 

[MarcVenice]

If you have a gigabyte NIC, you should be shot anyways.

 

[mxnerd]

I said gigabit, not GigaByte, I don't remember GigaByte selling gigabit NICs.

 

[MarcVenice]

Heh my bad, I was actually thinking you were referring to the KILLER NIC.

 

[dclive]

Originally posted by: mxnerd
In the forum I saw people saying bare minimum 300W is enough. But even with 80% efficiency, the output will be 240W max, and a lot of PSU is not 80% efficient, let's say it's 70%, then it's 210W under normal use. If under load the effeciency could be even lower.

Here's my question on that - I take it that a 300W PSU can *supply* 300W, not that it *uses* 300W. A 300W-supplying PSU would take about 20% more power (if it's 80% rated) in doing so, so "at the wall" it would suck about 360W of juice, give or take.

That's the difference in our figures.

 

[BoomerD]

My current rig uses about 350 watts from the wall, INCLUDING the 19" Sony CRT monitor, and that's while gaming. In " idle mode", the combo draws about 240 watts, and about 1/2 of that is the monitor. (Sony says 140 watts MAX) so in theory, I could probably replace my aging POS Aspire 500 watt PSU with a quality 400 watt unit and get by...but I'd rather spend a bit more and get one that will allow me enough power for future upgrades...Most likely, the Corsair HX 620, although there are a few others being considered.
I need to really tax the system and take Kill-A-Watt readings to see how much my system is actually capable of drawing from the wall.

Edit:
Removed the monitor from the Kill-A-Watt and ran 3DMark05...
133 watts...idle
275 watts MAX (briefly) during 3DMark 05 (most of the time it ran between 225 and 250 watts)
Downloaded a large file and burned a CD:
178 watts "idle"
285 watts MAX (briefly) during 3DMark05 (most of the time it ran between 240 and 260 watts.

I was surprised that "stressing the system" didn't make more of a load than it did, although my 3DMark05 scores suffered badly (dropped from 4905 to 3440)

 

[GalvanizedYankee]

Originally posted by: dclive
Can we get anyone with an engineering background (i.e. not a PSU marketing site) to say why we'd care about .9 TPF vs. .8 TPF, or .1 TPF, for that matter?

As I told you yesterday...Look through the PSU Forum over at Badcaps.net.
Go to jonnyguru.com>links and read.

 

[dclive]

If you see a specific post that looks interesting and talks in engineering terms, I'd love it if you'd share.

 

[GalvanizedYankee]

Originally posted by: dclive
If you see a specific post that looks interesting and talks in engineering terms, I'd love it if you'd share.

You appear to be a hard headed, young nerd, looking for fly poop in the pepper.

I am an old disabled diesel mechanic that used to repair engine control units that are mini-comps. I have had to rework the less-than designs of high paid engineers. They did their poor work in A/Ced offices.. I did mine under a make-shift cardboard roof because ambients were often 40C+ w/o shade and noise levels demanded ear plugs be worn. So I have no more time for this because my interest is where the rubber meets the road...not electronic theory.

PLEASE register at Badcaps and the techs over there will bury you in the most technical jargon and offer links that will demand an EE degree. Be sure to PM davmax into what you post. He is in his late 70s and has been designing electronic circuits since the days of tube radio...he is cracker jack sharp.

Only links I will/can offer.

http://www.fairchildsemi.com/an/AN/AN-42047.pdf
http://www.allaboutcircuits.com/vol_2/chpt_11/2.html
http://www.techarp.com/showarticle.aspx?artno=81&pgno=0

Now...Please offer this forum something besides Acer 300W.

 

[dclive]

Originally posted by: GalvanizedYankee

Originally posted by: dclive
If you see a specific post that looks interesting and talks in engineering terms, I'd love it if you'd share.

You appear to be a hard headed, young nerd, looking for fly poop in the pepper.

I am an old disabled diesel mechanic that used to repair engine control units that are mini-comps. I have had to rework the less-than designs of high paid engineers. They did their poor work in A/Ced offices.. I did mine under a make-shift cardboard roof because ambients were often 40C+ w/o shade and noise levels demanded ear plugs be worn. So I have no more time for this because my interest is where the rubber meets the road...not electronic theory.

PLEASE register at Badcaps and the techs over there will bury you in the most technical jargon and offer links that will demand an EE degree. Be sure to PM davmax into what you post. He is in his late 70s and has been designing electronic circuits since the days of tube radio...he is cracker jack sharp.

Only links I will/can offer.

http://www.fairchildsemi.com/an/AN/AN-42047.pdf
http://www.allaboutcircuits.com/vol_2/chpt_11/2.html
http://www.techarp.com/showarticle.aspx?artno=81&pgno=0

Now...Please offer this forum something besides Acer 300W.

It's unfortunate that asking for information sends you into a tizzy. Anyhow, thanks for the links.

 

[GalvanizedYankee]

T'is not sending me into a tizzy. How Elite are you if you can not find what you want once you are offered a direction?...like go over to Badcaps and mix with a few hard-core techs.

I am getting the distinct impression that you are an attention whore. Hope it is not true because they are time wasters.
Your next trick will be to complain about the links offered not being "tech" enough. Sheesh!

 

[dclive]

Now you're making this personal. I'm simply asking for information. If you don't like providing information, please don't reply.

As far as "attention whore", I'm simply making comments on how I see users' needs - based on Anandtech's own power reviews; I don't go into extensive detail on myself or my job history.

 

[Acanthus]

The PSU in my sig is $55 at newegg.

 

[Mark R]

Can anyone define this:
"with a true power factor of 0.9 or greater"

I don't know how much electrical theory and maths you know, hopefully this explanation is good enough.

Power factor is a curious property of AC circuits. Essentially, volts and amps are constantly changing in an AC circuit. The voltage rises to a peak, then falls to zero, then goes negative and back again. Because A and V are both changing continuously, so does Power (Volts x amps). As a result when one talks about '120 V' or '100 W' in an AC circuit, what they actually mean is the average taken over a period of 1/60 second. Ideally you want the amps to be proportional to the volts. If A is proportional to V, then you get optimal transfer of power from the grid to the device. If they aren't proportional, then there are some times when the amps flowing in the circuit are excessive for the amount of power being transferred.

This means you can calculate 2 values: 'real power' (or true power) which is calculated by instantaneously measuring V and I thousands of times a second, multiplying each measurement, and then calculating an average. This is an accurate measure of the actual energy being used. The other is 'apparent power' which is the 'average' volts x 'average' amps. This represents the amount of load on wiring, circuit breakers, transformers, etc. In an ideal circuit, these 2 measures will be equal. In circuits where A and V aren't proportional (because the device acts as a short term energy store), the 'apparent power' will be higher than the 'real power'.

The ratio between 'apparent' and 'real' power is 'power factor'. PF = 1 means optimal transfer of power. PF = 0.5 means that the 'average' current (amps) is twice what you would expect for the amount of 'average' power (watts) being transferred.

Can we get anyone with an engineering background (i.e. not a PSU marketing site) to say why we'd care about .9 TPF vs. .8 TPF, or .1 TPF, for that matter?

For home users, the benefit is pretty marginal:

The lower PF is, the more amps need to flow in the circuit to deliver power to your device. If you've got an uber-PC using 500W, if it has PF = 1, then it will need 500/120 = 4.2 A to run. If however, it has a more typical PF = 0.6, then it will need 500 / 120 / 0.6 = 7 A.
So, if you have a 15 A circuit for your computer room - you'd only be able to run 2 low PF PCs, but 3 high PF PCs from it. This may also be of benefit if you have a UPS, the lower current demands from the UPS will reduce operating temperatures and prolong battery life.

If you've got some kind of alternative energy system (e.g. off grid solar, gas generator, etc.) then it may also be in your interest to keep current down. That's pretty much it for home users.

Power/energy meters (this includes the main electricity meter at your property) always measure 'real power' (even the cheapest plug-in energy meters will measure real power). However, multimeters always measure apparent power because they measure volts and amps separately.

In the US, and many other countries, home electricity customers are charged only for 'real power'. The meters ignore the 'apparent power'. So, home users don't save a significant amount of money by changing to high PF (there is a marginal saving because you get less voltage sag in the wires in your home, but this is very marginal).

The people who win are businesses. Business electricity meters usually measure both 'real' and 'apparent' power, and bill them both seperately.

The next it gets pretty hardcore, so you can skip it if you want.

For highly technical reasons, 'true power factor' can be split into two components (both of which usually co-exist to some extent). 'Harmonic power factor' due to 'non-linear' electronic devices is far more troublesome than 'displacement power factor' due to motors or fluorescent lamps (inductive load) or capacitors. Some people make an effort of specifying 'true power factor' as some older techniques for calculating or measuring PF ignored harmonics. TPF basically means the actual ratio as described earlier.

Harmonic power factor is a problem, and it is for this reason, that some countries (notably European countries) now require electronic PSUs have PF > 0.95. This requirement isn't law in the US, and it's left up to the power companies to clear up the problems it causes. Office blocks have burned down because electricians and contractors didn't fully understand the significance of harmonic power factor, due to computers, on building power grids. Similarly, non-linear loads can interfere with other devices on the power grid - e.g. big transformers can overheat even when they are well within their 'apparent power' rating, and the performance of motors can be severely degraded if they share a grid with non-linear loads (the non-linear loads produce an electrical braking effect on the motor causing it to run badly - less torque, more vibration, more heat, poor starting). [Apart from the cost saving item, these additional benefits are only significant if a business has huge amounts of electronic devices - e.g. hundreds or thousands of PCs, or some extremely heavy duty electronic devices - e.g. industrial variable speed motors].

 

[John]

Originally posted by: dclive
As far as "attention whore", I'm simply making comments on how I see users' needs - based on Anandtech's own power reviews; I don't go into extensive detail on myself or my job history.

Please read this thread: http://forums.anandtech.com/me...074910&highlight_key=y

Mark R, that was one of the most detailed and informative posts that I have seen in quite some time. Thanks for sharing. :thumbsup:

 

[dclive]

Originally posted by: John

Originally posted by: dclive
As far as "attention whore", I'm simply making comments on how I see users' needs - based on Anandtech's own power reviews; I don't go into extensive detail on myself or my job history.

Please read this thread: http://forums.anandtech.com/me...074910&highlight_key=y

It's a good thread that clarifies that there's a range of results, but still most seem to stick in the 300W range, under load.

Kill-a-watt results from most posters are pretty consistently in that range as well.

Good post.