Help with Power Supply <$100, Stable Power

Page 2 - Seeking answers? Join the AnandTech community: where nearly half-a-million members share solutions and discuss the latest tech.

Bobthelost

Diamond Member
Dec 1, 2005
4,360
0
0
Originally posted by: VinDSL
Originally posted by: Bobthelost
It is indeed, he then said...
Hey, check out them idiots at Seasonic... :)
Here is what your computer power flow looks like:

Components -> PSU -> UPS -> Wall.

The components draw around 140W, the PSU loses 60W and your UPS shows 200W. PSUs are not rated by the power they draw from the wall or in your case, the power they draw from the UPS. Your entire analysis was flawed because you don't know that basic (and belive me, it's very basic indeed) fact.

I know what a power angel is, i know what it does. I don't have a clue what you think you're trying to prove except your ignorance.
 

Howard

Lifer
Oct 14, 1999
47,982
11
81
Originally posted by: VinDSL
Originally posted by: Zepper
I'd say it would be around 200-250W load on the PSU total. If you really want to know, you could get a P3 Kill A Watt. Multiply watts from wall by your efficiency factor to get approx what system is actually using...
Interesting!

I used the Calculator link that 'Baked' supplied. I *think* it's pretty accurate! It calculated 414W for my system rig. With his headroom recommendation, that would be 514W -- sounds prudent to me...

Now... I'm using an old Minuteman 300 UPS. Even with new batteries, it won't keep up with my rig, if the power goes out. The only thing I use it for is conditioning, e.g. filtering the power going to my rig. The thing is, it has an LED output load meter on it... and my rig idles at approx 200W. That's just the 'box', not the monitor, and so forth. When I do ANYTHING intensive, it pegs the display (300W). It's VERY possible that this thing is actually using 414W at 'the wall'... maybe more.

Anyway... this is hardly a high tech setup -- but I keep seeing ppl on this site recommending 380W power supplies, or whatever -- other saying you'll never use 550W, so you're just wasting your money -- et cetera.

How can this be?

Personally, I *think* 500-550W is *probably* the norm these days. I certainly wouldn't recommend less than that, unless I was punking someone. Is that what 'you guys' are doing -- horsing around with the n00bs? :)
Let me try to condense this:

1 - Your UPS, uh, does 300W or something
2 - Your rig idles at ~200W
3 - The display maxes out at 300W during intensive use
therefore
4 - your rig may be using the 414W the calculator suggested

Re: 2 - your rig may draw ~200W at idle from the wall, but it's almost certainly less than 150W from the PSU
Re: 4 - it doesn't follow. To get the amount of power the PC is using, you'd have to multiply the number the display shows (that is, if it went past 300W) by the efficiency. Assuming an efficiency of 75% (which might be stretching it considering the efficiency of your PSU is around mid-60s at low output), 300W shown on the display would mean about 225W is being used by your actual PC. And the output of any PSU is, of course, its output, not its intake/draw.

Of course that doesn't mean it's not actually using ~400W at load.
 

Howard

Lifer
Oct 14, 1999
47,982
11
81
And I see you're still clinging to that little joke of yours, in your My Rig page.
 

Praxis1452

Platinum Member
Jan 31, 2006
2,197
0
0
Why because...

Amps=Watts/Voltage

Watts=Amps x Voltage.

Watt's isn't really a relevant factor for psu's. Because when things draw power from the psu they draw from it at different voltages. Most of the power comes from the 12v rail. So even if your power supply has 500W most of it might be on the 5v rails and not on the 12v therefore you do not have enough power on the 12v rail.

Most people may draw around 250W-400W. So 500W psu's aren't really necessary. People buy them because it makes them feel better. It's not a need. Why do you think dell's etc all work fine with very small wattage psu's. They know how much power a system is going to need.
 

orangat

Golden Member
Jun 7, 2004
1,579
0
0
Originally posted by: VinDSL
Originally posted by: Bobthelost
Your entire analysis was flawed...
If I'm wrong, please tell me why, if you can provide links then that's even better. :)

What people are trying to tell you is that psu's are rated for their output, no links just plain psu-commonsense.
 

orangat

Golden Member
Jun 7, 2004
1,579
0
0
Originally posted by: modestninja
At this point it's one x1900xt 512mb, but thinking that Crossfire might be a possibility a year or two down the line.

modestninja, the x1900xt draws alot of power and the Enhance 5150 is a very good psu but it is insufficient.

The Enhance only has an 18A dedicated for everything else other than the cpu, and that includes the video card(s), fans, drives etc. The x1900xt was measured (at xbitlabs) to pull a max of 9A so a xfire setup could draw 18A at max. Silverstone has a single rail zeus model that is rated for high end sli and the quad rail zeus model would work also but it is probably more expensive.
 

acegazda

Platinum Member
May 14, 2006
2,689
1
0
In september, enhance is releasing a 5150gh version 3 that is identical to the silverstone element 500w, it has 36 amps combined on the 12v rails. This should be enough for a x1900xt xfire system.
 

orangat

Golden Member
Jun 7, 2004
1,579
0
0
Originally posted by: acegazda
In september, enhance is releasing a 5150gh version 3 that is identical to the silverstone element 500w, it has 36 amps combined on the 12v rails. This should be enough for a x1900xt xfire system.

How can that be sufficient when the 12V1 is capped off at 18-19A? An x1900xt can draw as much as 9A.
 

Praxis1452

Platinum Member
Jan 31, 2006
2,197
0
0
Originally posted by: orangat
Originally posted by: acegazda
In september, enhance is releasing a 5150gh version 3 that is identical to the silverstone element 500w, it has 36 amps combined on the 12v rails. This should be enough for a x1900xt xfire system.

How can that be sufficient when the 12V1 is capped off at 18-19A? An x1900xt can draw as much as 9A.
Because the pci-e slots provide 75W of power so therefore they will go through the main ATX connector and not draw off the pci-e which is on 12v2.
 

orangat

Golden Member
Jun 7, 2004
1,579
0
0
Originally posted by: Praxis1452
Originally posted by: orangat
Originally posted by: acegazda
In september, enhance is releasing a 5150gh version 3 that is identical to the silverstone element 500w, it has 36 amps combined on the 12v rails. This should be enough for a x1900xt xfire system.

How can that be sufficient when the 12V1 is capped off at 18-19A? An x1900xt can draw as much as 9A.
Because the pci-e slots provide 75W of power so therefore they will go through the main ATX connector and not draw off the pci-e which is on 12v2.

It doesn't matter whether the power comes from the pcie connector or the agp socket, both lines are on the same 12V rail. Unless the Silverstone does not follow the ATX12V spec to the letter and has some sort of rail fusion technology (which it doesn't), it will not supply more than around 18A for the video cards.

Combined 36A means jack for sli/xfire. The 12V1 rail for the ST50EF is capped off at 19A - as per manufacturers specifications.
 

Howard

Lifer
Oct 14, 1999
47,982
11
81
Originally posted by: Praxis1452
Originally posted by: orangat
Originally posted by: acegazda
In september, enhance is releasing a 5150gh version 3 that is identical to the silverstone element 500w, it has 36 amps combined on the 12v rails. This should be enough for a x1900xt xfire system.

How can that be sufficient when the 12V1 is capped off at 18-19A? An x1900xt can draw as much as 9A.
Because the pci-e slots provide 75W of power so therefore they will go through the main ATX connector and not draw off the pci-e which is on 12v2.
They might be supposed to do so... but in real life they don't provide any more than about 45W. It's all academic, anyway, since the 24-pin ATX plug and PCIe plugs are almost always on the same rail in a 2-rail supply, as orangat said.
 

VinDSL

Diamond Member
Apr 11, 2006
4,869
1
81
www.lenon.com
Originally posted by: orangat
What people are trying to tell you is that psu's are rated for their output...
Which output is rated? All they have is a single figure -- Blah Pro 550W or whatever...

If input doesn't mean anything, why do they 'rate' the efficiency of PSUs?

And, if wall current isn't important, why do they sell meters to 'rate' that?

Personally, I don't like 'black screens', 'blue screens', spontaneous reboots, reinstalling corrupted OS files, and all the rest of it. This guy wants a stable PSU for <$100 and I can understand that., but if he makes a choice based on techno-babble he's gonna be sorry, guaranteed!

It's like buying hamburger. Gimme $100 worth of watts -- the bigger the better. His computer ain't on a diet, so a little extra fat won't hurt!!!

All joking (and arguing) aside, this is what I would recommend today (3-Sept-2006)... ;)
 

Howard

Lifer
Oct 14, 1999
47,982
11
81
Originally posted by: VinDSL
Originally posted by: orangat
What people are trying to tell you is that psu's are rated for their output...
If input doesn't mean anything, why do they 'rate' the efficiency of PSUs?
You're brilliant. When did he say the PSU's draw didn't mean anything?
And, if wall current isn't important, why do they sell meters to 'rate' that?
Again, where did he say that? God damn.
Personally, I don't like 'black screens', 'blue screens', spontaneous reboots, reinstalling corrupted OS files, and all the rest of it. This guy wants a stable PSU for <$100 and I can understand that., but if he makes a choice based on techno-babble he's gonna be sorry, guaranteed!
What does this have to do with power draw from the wall and efficiency and whatnot?
 

Howard

Lifer
Oct 14, 1999
47,982
11
81
Was it necessary to reply to that?

You can certainly run a Crossfire rig on a PSU that costs less than $100.
 

Praxis1452

Platinum Member
Jan 31, 2006
2,197
0
0
Originally posted by: Howard
Originally posted by: Praxis1452
Originally posted by: orangat
Originally posted by: acegazda
In september, enhance is releasing a 5150gh version 3 that is identical to the silverstone element 500w, it has 36 amps combined on the 12v rails. This should be enough for a x1900xt xfire system.

How can that be sufficient when the 12V1 is capped off at 18-19A? An x1900xt can draw as much as 9A.
Because the pci-e slots provide 75W of power so therefore they will go through the main ATX connector and not draw off the pci-e which is on 12v2.
They might be supposed to do so... but in real life they don't provide any more than about 45W. It's all academic, anyway, since the 24-pin ATX plug and PCIe plugs are almost always on the same rail in a 2-rail supply, as orangat said.
Eh your probably right. However I think it's quite possible to run crossfire with 18 amps of power... Though of course this means that you had better not draw anything off of the 12v2. Or would the pci-e's be on 12v1?
 

VinDSL

Diamond Member
Apr 11, 2006
4,869
1
81
www.lenon.com
Originally posted by: Howard
Was it necessary to reply to that?

You can certainly run a Crossfire rig on a PSU that costs less than $100.
Okay... more academics then... :)

What's a X1900XT-512MB cost? Let's take a low ball of $300x2, or $600...

The OPER is looking for a <$100 PSU. What's wrong with this picture?
 

Howard

Lifer
Oct 14, 1999
47,982
11
81
Wow. Shall I repeat myself?
What are you trying to say?
If you think straw man arguments and evasion are good argumentation tactics, you're hardly worth replying to.
 

VinDSL

Diamond Member
Apr 11, 2006
4,869
1
81
www.lenon.com
Originally posted by: Howard
Wow. Shall I repeat myself?
What are you trying to say?
If you think straw man arguments and evasion are good argumentation tactics, you're hardly worth replying to.
Sorry, I was schooled in debate. Ad hominem attacks don't work on me. I'll call ppl on it every time, you included...

If you look back through this thread, you'll see when it started... why? Probably because I'm not a one-line lockstepper, like yourself.

I had one guy tell me "Power draw... is irrelevant", another tell me "Watt's isn't really a relevant factor for psu's", and so forth, and so on. So, now the game is afoot...

Judging apriori, I would say the OPER has no intentions of going with CrossFire. He just wants the option. I gave my recommendation twice, so I did my part. The rest of it is watching you monkeys slip and fall on banana peels!

Make more sense now?
 

Howard

Lifer
Oct 14, 1999
47,982
11
81
Originally posted by: VinDSL
Originally posted by: Howard
Wow. Shall I repeat myself?
What are you trying to say?
If you think straw man arguments and evasion are good argumentation tactics, you're hardly worth replying to.
Sorry, I was schooled in debate.
Bullshit. Where's the proof? And what was the personal attack, AS PERTAINS to your argument?
If you look back through this thread, you'll see when it started... why? Probably because I'm not a one-line lockstepper, like yourself.
At least I'm easy to understand. Now, I assume this is the line you're talking about:
Power draw as you're measuring it, with your UPS (or "the wall") is irrelevant for any reason other than billing
And he's right. Ignoring stuff like heat and noise, the only tangible difference for varying power draw is cost - so-and-so cents for a kWh or whatever you Americans use as an energy unit. Your reply to that:
Um... isn't that what Zipper (Ed: perhaps an intentional typo) just recommended measuring?
You completely missed the purpose of measuring it, though. He advised doing so to get the power draw of the SYSTEM. When Bob called you out on that, you didn't reply to it, but I must assume you read his response. Why bring it up again?

Next:
"Watt's isn't really a relevant factor for psu's"
Again, this is mostly correct. Oh, a PSU with lots of usable power must have a high power rating... but it is paramount that we understand this is not what we look for.
The rest of it is watching you monkeys slip and fall on banana peels!
What was that about ad hominem attacks? And if you honestly think you're that much wiser than the rest of us, you're even stupider than I thought.

EDIT: Would you please be so kind as to define "lockstepper"? If I understand correctly (after referring to m-w.com), I believe I am being called a sheep - that is, one that follows others while having no sense of individuality?
 

VinDSL

Diamond Member
Apr 11, 2006
4,869
1
81
www.lenon.com
Sheesh, Howard, calm down! I can hear your dentures clacking from here... :)

I'll go back and read your diatribe in one second, but since you asked, I was schooled in debate, conflict resolution, and public sector contract negotiations, etc, at the George Meany Center for Labor Studies in Silver Spring, Maryland. ;)