h-a-l-9000 wrote:

PCBONEZ wrote:

As overclockers can tell you undervolted parts use less watts.

Here you are wrong. A video card is not a simple ohmic power consumer at the 12V, but includes at least one switching regulator. When the input voltage gets lower the regulator increases the input current to be able to supply the same output voltage and current. This can go on until the input current becomes too high for the switching regulator and the protection kicks in.

That might be true for some parts of the card but not all of it.
There are ~20 amps of 3.3v in AGP that go directly to chips as Vcc and an additional ~2 amps of 1.5v that also does not go through a switching regulator.
There are ~2 amps of 5v that may or may not go through a switching regulator.
So what you are saying does not apply for up to 33 watts of the card's power.
.
The below pic is a screen shot out of the APG 3.0 Specification. Happened to be working on it for something else.
It shows the power through the slot. The blue is my notes.

Also many of the smaller VRs on mobos and add-in cards are LDO regulators which are not switchers and don't have PWM controllers or other driver chips.
They are often in packages that look just like MOSFETs but they don't work the same way.
It would be typical for the input to those to be 5v or 12v so some or all of the 5v and 12v may not even be going to switching regulators.
.

But even new high end, high power psu, don't have enough 5V wattage? I mean I've seen some 20A capable 650W psu when old 300W had more so I was thinking if you buy a 1000W psu they usually have or not enough 5V anyway?

386SX wrote:

But even new high end, high power psu, don't have enough 5V wattage? I mean I've seen some 20A capable 650W psu when old 300W had more so I was thinking if you buy a 1000W psu they usually have or not enough 5V anyway?

Iirc, this has been discussed here on Vogons even recently and one of the problems is the way modern PSUs have trouble supplying lots of 5v while 12v is barely getting used. They are typically made for supplying lots of 12v and supplying 5v only works well as long as the supplied amount of 12v is much higher...something like that 😜

386SX wrote:

But even new high end, high power psu, don't have enough 5V wattage? I mean I've seen some 20A capable 650W psu when old 300W had more so I was thinking if you buy a 1000W psu they usually have or not enough 5V anyway?

Those are the limits for the slot as allowed by the Spec. Cards are allowed to use up to that much but they don't necessarily do so.

Insofar as 5v in PCI (conventional) slots the 2 amp limit per slot is the same. PCI cards can use up to 10 watts of 5v if they want to.

PCI-Express is different. That one moved all the 5v loads to 3.3v. The PCI-E pinout doesn't even show one 5v pin.
http://pinouts.ru/Slots/pci_express_pinout.shtml

As it applies to systems needing 5v there isn't any point to overkilling watts if you aren't getting a strong 5v rail.
There are no doubt high watt PSUs that are intended for all PCI-E systems and they wouldn't likely have a strong 5v rail.
.

Thank. I have found some v2.1 psu with 48A on 5V, new but very cheap and very very light (with thin cables too...). I don't know if it's more dangerous to use an older one or these one...

386SX wrote:

Thank. I have found some v2.1 psu with 48A on 5V, new but very cheap and very very light (with thin cables too...). I don't know if it's more dangerous to use an older one or these one...

Which exact PSU is it?

386SX wrote:

Thank. I have found some v2.1 psu with 48A on 5V, new but very cheap and very very light (with thin cables too...). I don't know if it's more dangerous to use an older one or these one...

I wouldn't risk my stuff on a cheaply made PSU no matter what it's age.
Been there done that when I was young and stupid. Don't wanna do it again.

One of the reasons thin cables are bad is that they drop more voltage than thicker cables.
The longer a cable is the more voltage it drops.
There is a very cool calculator at the bottom of this page that will tell you wire voltage drops for AWG wire.
http://www.powerstream.com/Wire_Size.htm
It's more than one would think and given how tight the ATX spec is long thin wires can easily undervolt things.
.

It's a no brand no boxed... I bought it just as casual replacement but I had very bad experiences too with no branded psu (in the past I bought a new one that (casually tested) gave 17 volts on the 12v rail and 7 volts on the 5V rail, something like that...result, destroyed hd and almost the vga directly powered).

Tetrium wrote:

... one of the problems is the way modern PSUs have trouble supplying lots of 5v while 12v is barely getting used ...

Only if the PSU in cuestion is group regulated (cheaper). When it's independent (Indy) regulation, or DC-DC, they can deal with unbalanced loads (like heavy draw from +5V while light load on +12V).

Aris Mpitziopoulos (one of the best PSU reviewers out there nowadays) explains the three regulation types in this Tom's Hardware article:

PSUs 101: A Detailed Look Into Power Supplies

Paradoxically, modern Intel CPUs (from Haswell onwards) while in C6/C7 sleep states pose for the PSU the same problem than the venerable Athlon XPs (unbalanced load with heavier +5V than +12v). That's why you need an Indy or DC-DC PSU to run Haswell/Skylake systems (unless you disable C6/C7 sleep states in BIOS).

Godlike wrote:

PCBONEZ, you are typing about this brand?

Yes that is the brand. - Sorry it took so long. Wrote it yesterday but I had to be somewhere and I forgot to click submit.

Delta are usually very solid reliable PSUs and it's one of the few where if it says it's x-many watts it really is x-many watts.
PSUs have a Peak rating and a Continuous rating.
The less honest brands give you the Peak rating. The more honest brands give the Continuous rating.
Delta gives the Continuous rating or both. - Now look at the label in your photo. It shows both.

Many Delta were sold OEM so there are a lot of them out there.

One thing to watch out for is that some Dell OEM ATX PSUs for P3 [and maybe older] used a proprietary pinout with the standard connector.
The connector looks the same but the voltages are in different places across the connector.
That is not a Delta thing. It's a Dell thing and it applies to any PSU brand Dell used at that time.
Brought it up because Dell did use a lot of Delta PSUs.
I said 'some' earlier because not all Dell P3 PSUs were like that but many were.
So either avoid Dell P3 PSUs or research before you buy.
There are also adapters to convert Dell proprietary to standard or back.
.

PCBONEZ wrote:

... Delta are usually very solid reliable PSUs and it's one of the few where if it says it's x-many watts it really is x-many watts ...

Indeed, even budget Delta designs like the Antec VPF's (known as EA-xxx GREEN in the USA) are quite decent PSUs.

Delta's workmanship is also generally immaculate.

Godlike wrote:

PCBONEZ wrote:

Many people have learned how to rebuild used older PSUs so they can get what they want.

"Many people" please open thread and share your knowledge about keeping most important part in retro personnal computer in great shape. please

To get the basics down the link TELVM gave you PSUs 101: A Detailed Look Into Power Supplies and this Anatomy of Switching Power Supplies are very good places to start.
I disagree with parts of PSU's 101's "Capacitors Manufacturer Tier List" but the "First-Tier" is okay with select SamXon added, so I'm not going to bother arguing levels of bad.
.
I am more of a motherboard and capacitor guy than a PSU guy. Chasing capacitors eventually lands you inside PSUs and I've learned enough to fix my own. Some sections I know really well. Others not so much. I probably know more than the average but there are a whole lot of people that know more than I do. I haven't been on Vogons long but I think a few here might.

The Badcaps.net forum and Hardwareinsights.com forum both have people that do things like rebuild their own PSU transformers and design custom mod circuits. Many of the members are on both sites.

Badcaps.net started all about motherboard capacitors but since has branched into PSUs, LCD screens (TV and monitors), a bit of audiophool stuff and other things.

There was a young member of Badcaps.net that lived in a crap town (I used to drive through it to work). He was really smart but he had way too much energy so he kept getting into trouble both in RL and on the site. He got banned for a while but I talked TC (the owner) into letting him back in. I suggested to him (the kid) that he divert some of his energy towards creating a site about something he was interested in. I didn't think he would take my advice, but he did. He created hardwareinsights.com which at first was all about PSUs. A few years later he handed the site over to Behemot. ( I assume and hope he found a way into college and didn't have the time for a site.) Beyond being the administrator there Behemot is a Badcaps.net member and important to know for two reasons. He is one of those that custom designs PSU mod circuits. He orders custom capacitor sizes direct from Japanese manufacturers that are often needed for PSUs but are very hard to find. Soon he may be the only source for Japanese 3300uF 16v in 10mm with ESR appropriate for PSUs. His stock list is HERE He is in Prague, CZ. I have not personally ordered from him yet but I would. ( I currently have 30,000+ capacitors in stock and I'm not working ATM. )

You can also learn at lot at review sites that "go deep" by tearing the PSU apart to look at the internals and/or use an O'Scope.
The following usually do that. (Bear in mind Hardwareinsights is not run as a full time occupation.)
Hardwareinsights PSU reviews.
Hardwaresecrets PSU reviews.
Jonnyguru PSU reviews.
There are others. This is just a starter.
.

TELVM wrote:

Only if the PSU in cuestion is group regulated (cheaper). When it's independent (Indy) regulation, or DC-DC, they can deal with […]
Show full quote

Tetrium wrote:

... one of the problems is the way modern PSUs have trouble supplying lots of 5v while 12v is barely getting used ...

Only if the PSU in cuestion is group regulated (cheaper). When it's independent (Indy) regulation, or DC-DC, they can deal with unbalanced loads (like heavy draw from +5V while light load on +12V).

Aris Mpitziopoulos (one of the best PSU reviewers out there nowadays) explains the three regulation types in this Tom's Hardware article:

PSUs 101: A Detailed Look Into Power Supplies

Paradoxically, modern Intel CPUs (from Haswell onwards) while in C6/C7 sleep states pose for the PSU the same problem than the venerable Athlon XPs (unbalanced load with heavier +5V than +12v). That's why you need an Indy or DC-DC PSU to run Haswell/Skylake systems (unless you disable C6/C7 sleep states in BIOS).

Thanks for giving additional info 😀

Btw, what are Indy or DC-DC PSUs?

And PCBONEZ, thanks for the links! I'm reading them right now!
But the table with the PSU brands here http://www.tomshardware.com/reviews/power-sup … nds,3762-4.html how can I download them?
Maybe I'm just not seeing something but I can't click the table (it's a pic but it seems to just be the thumbnail without a link to the really big table), help? 😵
I want that info 😁

Indy = Independently regulated, adjusting one voltage output (12V for instance) does not necessarily change the 5V or 3.3V supply voltage
DC-DC = switch mode step down (buck) converters are used to create the 5V and 3.3V outputs from the 12V supply

gdjacobs wrote:

Indy = Independently regulated, adjusting one voltage output (12V for instance) does not necessarily change the 5V or 3.3V supply voltage
DC-DC = switch mode step down (buck) converters are used to create the 5V and 3.3V outputs from the 12V supply

Thanks. Learned something new today 😀

Kreshna Aryaguna Nurzaman wrote:

Then I imagine a 700 watt Thermaltake TR2 700 should be enough for the following system: […]
Show full quote

luckybob wrote:

^^^ basically true.

The majority of NEW power supply designs, they are designed to make +12. THEN they put in a dc/dc converter for the 5v and 3.3v. This means you can basically load it however you want to. A Pentium 3 wont stress a quality psu to any significant degree. A P4 will, but most of them are designed for high 12v loads.

moral of the story; get a quality unit, and forget about it.

Then I imagine a 700 watt Thermaltake TR2 700 should be enough for the following system:

Intel 440BX
Pentium III 600
Voodoo5 5500 AGP
Voodoo Graphics
Diamond MonsterSound 3D
Sound Blaster AWE 64 Gold
Thrustmaster ACM Game Card
Yamaha SW60 XG

Yup, basically it has one AGP card, two PCI cards, and three ISA cards. A modern 700 watt PSU should be enough, no? The TR2 has 24A from its +5V.

I use a Thermaltake TR2 500 with the machine in my signature for some time now, so I think yours will be ok with a 700.

Tetrium wrote:

But the table with the PSU brands here http://www.tomshardware.com/reviews/power-sup … nds,3762-4.html how can I download them?
Maybe I'm just not seeing something but I can't click the table (it's a pic but it seems to just be the thumbnail without a link to the really big table), help? 😵
I want that info 😁

Seems to be a mistake in their page coding.
Bypassing their code and using a direct link seems to work. (click on it to expand)
.
http://media.bestofmicro.com/L/E/424562/original/psu-a-b.png
.

PCBONEZ wrote:

Seems to be a mistake in their page coding. Bypassing their code and using a direct link seems to work. . […]
Show full quote

Tetrium wrote:

But the table with the PSU brands here http://www.tomshardware.com/reviews/power-sup … nds,3762-4.html how can I download them?
Maybe I'm just not seeing something but I can't click the table (it's a pic but it seems to just be the thumbnail without a link to the really big table), help? 😵
I want that info 😁

Seems to be a mistake in their page coding.
Bypassing their code and using a direct link seems to work.
.

It worked, cheers!

The second page had the same problem which was easily solved using the same bypass method. The remaining pages were like they were supposed to be 😀

tayyare wrote:

Kreshna Aryaguna Nurzaman wrote:

Then I imagine a 700 watt Thermaltake TR2 700 should be enough for the following system: […]
Show full quote

luckybob wrote:

^^^ basically true.

The majority of NEW power supply designs, they are designed to make +12. THEN they put in a dc/dc converter for the 5v and 3.3v. This means you can basically load it however you want to. A Pentium 3 wont stress a quality psu to any significant degree. A P4 will, but most of them are designed for high 12v loads.

moral of the story; get a quality unit, and forget about it.

Then I imagine a 700 watt Thermaltake TR2 700 should be enough for the following system:

Intel 440BX
Pentium III 600
Voodoo5 5500 AGP
Voodoo Graphics
Diamond MonsterSound 3D
Sound Blaster AWE 64 Gold
Thrustmaster ACM Game Card
Yamaha SW60 XG

Yup, basically it has one AGP card, two PCI cards, and three ISA cards. A modern 700 watt PSU should be enough, no? The TR2 has 24A from its +5V.

I use a Thermaltake TR2 500 with the machine in my signature for some time now, so I think yours will be ok with a 700.

Ah, thank you.

I just wonder; from which rail do ISA and PCI devices draw their power? For example, dld sound card like SBPro 2.0 and Roland LAPC draw their power from 5V- rail, but how about Yamaha SW60XG? How about Thrustmaster ACM gamecard? Or how about Voodoo5 5500 APG? The Voodoo5 uses PSU disk drive connector, but the manual doesn't mention whether it uses 12V+ or 5V+, so how am I supposed to know? So far, it's been "plug and pray" for me, but it'll be better if I know exactly what I'm doing.