nforce4max wrote:

40w max is likely about right seeing they really don't put out much heat and the rest of the card is often stone cold, typical or average load is likely 25 or 30w.

No.
The Voodoo5 5500 has two 15w GPUs so it's essentially two 15+ watt video cards built onto one PCB. - 30+ watts.
The CPU is 5v powered and after VRM efficiency can pull up to 50 watts from the PSU at full CPU load.

3.3v+5v is already at 80+ watts - without considering the loads from the actual motherboard, RAM, drives or the other 5 add-in cards.

40 watts might cut it at idle, that's about it.

For their SE440BX2 board Intel gives the 3.3v+5v load at idle (at DOS prompt) using a low end video card (and no other cards) and 48Mb RAM as 24 watts.
That would be a very basic office computer at idle, hardly a gaming system.

It's not just the +5v that causes the problem.
3.3v+5v combined watts on modern PSUs is hard to find at 150 watts or more.
BX vintage correct PSUs often had 3.3v+5v combined watts limits in the 185w-230w range and there was a real reason for that.

The other reason you have to overkill the crap out of watts using modern PSUs is the get a high enough 3.3v+5v watts rating.
One with less than 150 watts (3.3v+5v) probably isn't going to cut it for a BX based gaming system with 6 add-in cards.
With the parts selection I would call this one a BX based EXTREME gaming system and even 150 watts (3.3v+5v) is iffy IMHO.
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By the way it still seems incredible nowdays to have 1000W on a multiple rail and 150w on another..

PCBONEZ wrote:

nforce4max wrote:

40w max is likely about right seeing they really don't put out much heat and the rest of the card is often stone cold, typical or average load is likely 25 or 30w.

No.
The Voodoo5 5500 has two 15w GPUs so it's essentially two 15+ watt video cards built onto one PCB. - 30+ watts.

We still have not figred out how much of the power the board needs come from the 5V rail, which is the main issue with choosing the PSU.

alexanrs wrote:

PCBONEZ wrote:

nforce4max wrote:

40w max is likely about right seeing they really don't put out much heat and the rest of the card is often stone cold, typical or average load is likely 25 or 30w.

No.
The Voodoo5 5500 has two 15w GPUs so it's essentially two 15+ watt video cards built onto one PCB. - 30+ watts.

We still have not figred out how much of the power the board needs come from the 5V rail, which is the main issue with choosing the PSU.

Couldn't this be somewhat guessed by calculating it's GPU power dissipation (by die size, GPU voltage, GPU frequency and perhaps its manufacturing process) compared to contemporary GPUs?

Another possibility could be to measure total power dissipation and then underclock the card (if that's possible).

Both these ways aren't very accurate though, but it's beats guessing.

A few posts ago a close photo of the AUX power plug showed that both 5V and 12V had circuitry associated with them. So we don't really know what is being powered from the 5V rail and what is being powered from the 12V rails. Total consumptions should not be hard to estimate, but rail-specific draw is another matter.

alexanrs wrote:

A few posts ago a close photo of the AUX power plug showed that both 5V and 12V had circuitry associated with them. So we don't really know what is being powered from the 5V rail and what is being powered from the 12V rails. Total consumptions should not be hard to estimate, but rail-specific draw is another matter.

I know, sorry, I wasn't really paying attention 😊
But at any rate, to measure is to know, measure it from the molex. Perhaps use a molex adapter with its 12V line severed?
Could even be reversed (cut the 5V on the molex), perhaps Voodoo 5s were made to do either???

Yes I know this may be risky

alexanrs wrote:

PCBONEZ wrote:

nforce4max wrote:

40w max is likely about right seeing they really don't put out much heat and the rest of the card is often stone cold, typical or average load is likely 25 or 30w.

No.
The Voodoo5 5500 has two 15w GPUs so it's essentially two 15+ watt video cards built onto one PCB. - 30+ watts.

We still have not figred out how much of the power the board needs come from the 5V rail, which is the main issue with choosing the PSU.

When you know the GPU TDP in watts and are looking at the 3.3v+5v combined watts how much is specifically on 5v doesn't matter.
That is why I chose to look only at 3.3v+5v combined watts in that post.

The thing is the GPU power use is only part of the card's full power use, which is why I said 30+ watts vs just 30w.
I don't actually know if the 15 watts is just for the GPU or a whole card using that GPU.

The reports online about the Voodoo5 6000 with 4 VSA-100 GPUs are fairly consistent at 60-70 watts so a card using 15 watts/GPU (for VSA-100 GPU) seems reasonable for the sake of discussion.

The Voodoo5 5500 has two VSA-100 so in theory it's 3.3v+5v watts (at the chips) should be about 30 watts.
Strictly speaking AGP slots are capable of providing 48.25w so that card shouldn't need a supplemental power connector.
Yet it has one. I'm not sure why they did that. Might even just be a marketing ploy.
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Oops, I did all my math using the Voodoo5 6000 as the basis, not the 5500, my bad.

I was talking about how much power came from 5V rails and how much came from the 12V, and I did that math assuming part of the load went to the 12V rails, but assuming a slightly uneven distribution favouring heavier loads on the 5V one. For the PSU with two 15W chips I'd overestimate it to draw 40W in total (due to associated circuitry). My previous math is still good enough assuming most of it comes from the 5V rails, but if not it should knock down the requirements a bit if not.

Anyway, would it be possible to do something like put some black isolating tape isolating the 5V power pins on the AGP slot, have the card draw nearly all of its power from the molex connector and then measure the loads? Might be overkill just for this, but it could be interesting.

Voodoo cards I've personally looked at concerning power distribution (Voodoo2, Voodoo3 2000/3000) have one or more 5v-to-3.3v POL (Point of Load) step-down regulators on the card.
This tells me the chips themselves are using primarily 3.3v -and- a lot of the power is coming from +5v.

Passing the power using a higher voltage than needed and then using a step-down POL regulator near the ICs (or slots) is common practice in electronics.
The higher voltages require less amps for the same watts.
That (less amps) means smaller conductors and traces can be used for the longer distances. (And fewer pins for that matter.)
Smaller traces take up less board space which is important for trace heavy parts like motherboards and some add-in cards.
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I have traced-out dual voltage PCI cards (can use either 3.3v or 5v power) and at least some detect if 3.3v is present from the slot.
If it is not present they use 5v-3.3v step-down step down regulators.
If it is present they turn off the 5v regulators and draw 3.3v directly from the slot.
I can't say they all do that but some do.
There isn't going to be a huge difference in 3.3v-5v combined watts but on 5v they would use a little more power due to losses in the step-down process.
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386SX wrote:

By the way it still seems incredible nowdays to have 1000W on a multiple rail and 150w on another..

Modern hardware demands tons of +12V but very little +5V & +3.3V, so modern PSUs are tailored accordingly.

Just like they were tailored the opposite way in 2000, when the reverse was true:

It could be worse, think about the extinct -5V rail ...

TELVM wrote:

Modern hardware demands tons of +12V but very little +5V & +3.3V, so modern PSUs are tailored accordingly. […]
Show full quote

386SX wrote:

By the way it still seems incredible nowdays to have 1000W on a multiple rail and 150w on another..

Modern hardware demands tons of +12V but very little +5V & +3.3V, so modern PSUs are tailored accordingly.

Just like they were tailored the opposite way in 2000, when the reverse was true:

It could be worse, think about the extinct -5V rail ...

Yeah and in fact I look around a lot to find some new old power supply with strong 5v rail. But I was wondering with all that incredible power on the 12v they could let anyway a bit more on the 5V rail even from a compatibility point of view and even if it would not be usually used.

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TELVM wrote:

IMHO Kreshna's system (single PIII 440BX) will never draw as much as 175~200W from +5V.

Not on a modern PSU it won't. - Because modern PSUs can't even handle 175~200W from +5V.
Modern PSUs with more than a 130 watts COMBINED 3.3v+5v limit are rather hard to find unless looking at PSUs over $75-$85.
Even over $75-$85 the typical max COMBINED 3.3v+5v watts available peaks at around 150 watts. - No way it is going to do 175~200W from +5V.
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TELVM wrote:

My guess is that it will not draw more than 100~125W from +5V, and probably less. A PSU rated 20~24A on +5V and 130~150W or so combined should suffice for his system.

Yet - I've seen at least 3 people in the last couple weeks report that 20-25(ish) amps (on 5v) wasn't adequate on their similar 5v-CPU gaming systems.
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Their complaints make total sense as 350w ATX12V PSUs of "20-pin vintage" typically had in excess of 30a on +5v and 3.3v+5v combined was in the range of 185w-230w or more.
(Considering a 350w PSU as era correct "gaming class" for this.)
A 350w providing 30(plus) amps on 5v and >200 watts 3.3v+5v combined would not have been so common as to be *the rule* if no one needed it.
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[examples - looked at "modern" ATX12V v2.3x compliant, 400-750w, $50-$75 price range, minimum of 20a +5v]
Note: 5v amps - 3.3v amps and Combined 3.3v+5v Watts, are in bold. (Click on make/model to see ad.)
.
Thermaltake SMART SP-650AH2NCB 650W ............ 24a-24a 120w
Thermaltake SMART SP-750AH2NCB 750w ............. 25a-25a 130w
SPARKLE SPI500ACH8-B204 500W ....................... 24a-24a 123w
Corsair CX430M 430W .......................................... 20a-20a 110w
Corsair CX500M 500W .......................... 20a(5v)-25a(3.3v) 120w
Corsair CX600M 600W .......................................... 25a-25a 130w
Corsair CX750M 750w .......................................... 25a-25a 130w
SeaSonic SS-400ES Bronze 400W .......................... 20a-20a 130w
SeaSonic SS-500ES Bronze 500W .......................... 24a-24a 130w
SeaSonic SS-500ET Bronze 500W .......................... 24a-24a 130w
Cooler Master Elite 460W ..................................... 20a-20a 130w
~~
~~
In looking I didn't see -ANY- ATX12V v2.3x PSUs with more than 130w combined 3.3v-5v for 75$ or less. (Same for over 25a +5v.)
In the $75-$100 range I saw a few with more than 130w (1@ 160w, most 150w or less) but it was spotty even in that $ range.
So: If you intend to use a brand new PSU in an old very 5v heavy system you should be looking at $85-$100+ PSUs first.
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So lets look at a few old-spec 350 watt PSUs for comparison.
Most of these are ATX12V v1.xx w/20-pin mobo power connectors.
- Focus on the combined watts as compared to above. (In addition to just +5v amps.)
.
Thermaltake W0118RU v1.3 ... 350w 30a(5v)-20a(3.3v) 185w
Enermax EG365P-VE .............. 350w 32a(5v)-32a(3.3v) 185w
Antec SmartPower SL350 .........350w 35a(5v)-28a(3.3v) 230w
HiPro HP-P4017F4W .............. 350w 32a(5v)-20a(3.3v) 210w
Seasonic Super Silencer ......... 350w 30a(5v)-28a(3.3v) 200w
Cooler Master RS-380-PMSR .. 350w 32a(5v)-20a(3.3v) 210w
Rosewill AP-400X .................. 350w 35a(5v)-28a(3.3v) 200w
Austin DR-B350ATX ............... 350w 35a(5v)-28a(3.3v) 200w
.
So 30a(plus) on 5v and combined 3.3v+5v watts of 185-230w were NORMAL back in the day.
Why would anyone expect a GAMING system from back in that day (let alone an extreme one like Kreshna is building) to need less today?
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I did collect photos of the labels for all of the old ones showing the specs but as this got so long I'm going to skip uploading those.
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Me, I would rather recap an old ATX12V v1.xx which usually costs (me) under $40-$45 including the caps, PSU and shipping costs.
That is partly because modern PSUs don't necessarily have good caps anyway so buying new doesn't avoid the root problem.
When the planets align I can pull it off for $25-$30 (vs the $85-$100+ for a new model) and take the wife out for a big fat ribeye and margaritas.
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386SX wrote:

By the way it still seems incredible nowdays to have 1000W on a multiple rail and 150w on another..

I agree.
There is no reason they can't build the combined 3.3v+5v watts to a more respectable limit.
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IMHO multiple 12v rails to feed add-in cards is a poor engineering practice to start with.
Lets say 12v1 is at 11.5v and 12v2 is at 12.5v.
Both are within the ATX spec but there is a 1 volt difference.
If you feed the card 11.5v at the slot -and- 12.5v via an aux connector the voltages are going to try and balance THROUGH the card which means more current through and more heat in the traces.
As the shortest electrical path is likely through just the traces the resistance would be very small so even with just 1 volt the current could be significant.
.
If the slot power is isolated from the aux power by not connecting the traces through the card that would be a non-issue but I'm not confident cards are built that way.
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PCBONEZ wrote:

I've seen at least 3 people in the last couple weeks report that 20-25(ish) amps (on 5v) wasn't adequate on their similar 5v-CPU gaming systems ...

I'd guess none of those systems is a frugal single PIII 440BX. Probably more power hungry Athlon Classic/XP without 'P4 connector' on mobo.

PCBONEZ wrote:

Me, I would rather recap an old ATX12V v1.xx ...

Me too, but most vogoners can't recap, and 10~20 year old caps could not be reliable.

TELVM wrote:

PCBONEZ wrote:

I've seen at least 3 people in the last couple weeks report that 20-25(ish) amps (on 5v) wasn't adequate on their similar 5v-CPU gaming systems ...

I'd guess none of those systems is a frugal single PIII 440BX. Probably more power hungry Athlon Classic/XP without 'P4 connector' on mobo.

1999 Athlon Classics, 31-55w
Last Gen AGP 1x/2x = Riva TNT, <15w (assumed in your favor as undocumented, a 7300GT is 16w, Voodoo3 2000/3000 is 15w)
31-55w + 15w = 46-70w

1999 Pentium III 600 Katmai, 34.5w (He specified.)
Voodoo 5 5500, 30w watts
34.5w + 30w = 64.5w

Looks to me like the 'power hungy' Classic Athlon is more likely to use LESS power than this BX configuration.
If more it would only be 5.5w more.
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Hint Hint: He could knock 18.7 watts off by upgrading to a 600MHz coppermine - if it will run.
.
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TELVM wrote:

PCBONEZ wrote:

Me, I would rather recap an old ATX12V v1.xx ...

Me too, but most vogoners can't recap, and 10~20 year old caps could not be reliable.

IMHO being into retro electronics and not knowing how to solder and to replace caps is like shooting yourself in the foot repeatedly.
Every time something comes up (and it will repeatedly, more so as things age) - BANG, you lose.
.
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I think that even if I could recap power supply capacitors assuming it could be easier to repair of some game console I did, the problem for me would be how to test it under stress without risking to break a whole connected system. And generally a bit of fear in the case something would go wrong not immediately but later.

I am looking at a new/old v2.1 psu to understand how things are inside. This is a rebranded cheap psu that should have 48A on the +5v and total of 500W. I see these kind of capacitors:

2 bigger caps Dexon 200v/470uf
2 medium-small Lowesr
2 medium unbrand HB CD288
2 medium-small ThengX
1 another small ThengX

But the Barton 3200+ can't power on this.

the PSU I'm currently running on my PII 400/440bx/9500PRO (a card which uses AGP + additional power connector) seems to deliver 120W for 3.3 and 5v combined,
it doesn't really have stability problems, but it's from an unknown age, and not popular brand.
I tested with my kill a watt clone and the power usage while gaming is 85W total, doing some burn tests I might be able to get 90W at the wall, sitting on the desktop doing nothing already eats 81W, in any case the PSU seems to operate pretty hot, replacing the 9500PRO for a voodoo 4 4500 lowers the power by a little over 15W while playing the same game with similar framerate.

I'm thinking about buying a few more PSUs but, it's hard to find anything interesting here, I looked at some Deltas which are on my price range but I can only find some 300W model with 125W for 3.3+5v and others like the one I'm currently using

386SX wrote:

I am looking at a new/old v2.1 psu to understand how things are inside. This is a rebranded cheap psu that should have 48A on th […]
Show full quote

I am looking at a new/old v2.1 psu to understand how things are inside. This is a rebranded cheap psu that should have 48A on the +5v and total of 500W. I see these kind of capacitors:

2 bigger caps Dexon 200v/470uf
2 medium-small Lowesr
2 medium unbrand HB CD288
2 medium-small ThengX
1 another small ThengX

But the Barton 3200+ can't power on this.

Okay,

The 200v caps rarely need changed. Those are on the AC side and short of a power surge they usually last.
If they are flat on top, not leaking and less than (say) 20 years old I wouldn't bother with them.

For the others if you give me everything written on them and any logos I might be able to figure out what they are.

Are you sure the ThengX don't actually say ChengX?
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SPBHM wrote:

I'm thinking about buying a few more PSUs but, it's hard to find anything interesting here, I looked at some Deltas which are on my price range but I can only find some 300W model with 125W for 3.3+5v and others like the one I'm currently using

Deltas are generally good solid reliable PSUs and a 300w Delta can probably support more actual load than a 350-400w no-name brand.
Delta gives the continuous power (full time) whereas no-name brands give the peak power (short time) ratings.
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Random thoughts/comments.
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That you game adds less than 10w over the desktop tells me it's not particularly stressful to that system.

P-II 400 is 24.3w before considering VRM efficiency.
Using 75% efficiency it would be about 32w (at 100% utilization) at the PSU.

Vintage correct PSUs had AC-to-DC efficiencies like 65-75% - Using 75% again for simplicity
90w at the wall would be about 67w on the DC side.

Thus far I haven't found out anything useful about the Radeon 9500 PRO or even about a card with the same chip.
With an aux connector it's max is probably over 50w and I did see a 'low confidence' guess of 75w.
A 15w drop to the 30w (max) Voodoo suggests it's not using over 45w, but that might be the application isn't stressing it.

(This is WAY ball-parking it:)
If we say the PSU is stressed to under 70% (~22w) and the card is actually using the full 45w (not likely, based on Voodoo maxed +15w) then 85-90w at the wall is reasonable.
The CPU and card are probably using a little less and the other loads are making up the difference.
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