A lot of older systems were heavy on the 5v rail rather than 12v rail like modern machines are. I know this was certainly the case for Athlon Thunderbird and Athlon XP systems, perhaps it’s the same for Super Socket 7?

What kind of power can your PICO deliver on the 5v rail, and how does that compare to your ATX PSU?

pico PSUs usually do less than 10A on 5V, that's simply not enough, like said later systems that rely on 12V are better suited, but if you're not using HDDs or other power hungry drives they also work really nicely for lower tier systems like 486 and below.

I performed some tests recently.

This:

(uses ISL6440 controller - one for both +3.3V and +5V)

with a heatsink glued to +5V mosfets and active cooling (fan on the PSU) Pentium 3 with GF3 Ti 200 and a single laptop drive would be max, but it's pushing it. This PSU will not turn on at all when too much current is drawn on startup.

This:

I acquired it only recently, i managed to squeeze around 100W of power on +5V rail... (overclocked/overvolted Athlon!) but i did NOT perform any long-term tests. So I cannot recommend it yet.
It uses two RT8015 controllers (one for +5V and one for +3.3V) and has really good low resistance MOSFETs (M3058M).

It seems to have no real thermal protection, so without fan and heatsink the temperature rises over 110*C. Definitely not safe to use in these conditions. Maybe it would turn off at some point, but I didn't want to run it like that for too long. With a heatsink on +5V mosfets and low RPM fan over it around 60 degrees C on the coil, 78 degrees on MOSFETs heatsink.

When drawing only 80W of power, the temps are much better than that.

But I have no idea about ripple and other specs, some measurements with oscilloscope would help...

Edit: updated images and temps.

150w pico psu from eurocase: 5A on 5V
525w ATX: 24A on 5V

(btw the best pico psu that i could find (picoPSU-160-XT from mini-box) has 8A on 5v)

but i did not expect super 7 requirements to be that different from socket 7

mojmir wrote on 2021-06-05, 18:25:

150w pico psu from eurocase: 5A on 5V
(btw the best pico psu that i could find (picoPSU-160-XT from mini-box) has 8A on 5v)

These ratings unfortunately are often completely useless without performing real tests.

I also have this one and it seems to be most powerful, but it's also the largest https://www.pico-box.com/en/catalogue/dc-atx- … p/9/x1-atx-200/

Original cooler is not mounted very well, so I suggest beefing the cooling up with an additional aluminum profile, thermal pads and long screws... (originally it only has top heatsink with some thick thermal pads)

adalbert wrote on 2021-06-05, 18:34:

These ratings unfortunately are often completely useless without performing real tests. […]
Show full quote

mojmir wrote on 2021-06-05, 18:25:

150w pico psu from eurocase: 5A on 5V
(btw the best pico psu that i could find (picoPSU-160-XT from mini-box) has 8A on 5v)

These ratings unfortunately are often completely useless without performing real tests.

I also have this one and it seems to be most powerful, but it's also the largest https://www.pico-box.com/en/catalogue/dc-atx- … p/9/x1-atx-200/
x1atx200.jpg

Original cooler is not mounted very well, so I suggest beefing the cooling up with an additional aluminum profile, thermal pads and long screws... (originally it only has top heatsink with some thick thermal pads)
pico2.jpg

their website also lists a 500W model, though no place listed to buy any of their products, nor any details on what the max power/voltagerail is...
googling for the product numbers does list results for some of their products.

weedeewee wrote on 2021-06-05, 19:08:

their website also lists a 500W model, though no place listed to buy any of their products, nor any details on what the max power/voltagerail is...
googling for the product numbers does list results for some of their products.

It's a bit buried, but:
https://www.pico-box.com/media/support/202105 … 0-Datasheet.pdf

12A on 5V, needs a 16V-28V supply.

many thanks for all your responses, i fell asleep while putting kids to bed, sorry

ok, so in theory max system would be something along pentium3 which what i cca expected.
i still do not understand much why the same combo (socket7 board, s3 vga, k6-2 cpu) does start without problems, but the same on super7 board does not start at all. maybe try some low power k6?

one more question:
- when did the transition to 12v happen? (i.e. what are those systems that rely more on 12v? pentium4? and on amd side?)

Basically yes, the introduction of the P4 and it’s 4-pin 12v connector for dedicated CPU power was the start of the move to 12v heavy systems.

Of course P4s weren’t particularly power efficient, so you’d probably have better luck with a low-power variant of a core 2 duo than a P4, particularly a Willamette or Prescott (though a lower TDP Northwood might be OK). There was a reason that a lot of laptop manufacturers kept with P3 during early P4 days, and why they jumped to Centrino (Core Solo/Core Duo) as early as possible.

I've been using a Chinese picoPSU knock-off and a power brick from RGEEK - both rated at 120W, - for over 3 years now on a permanent basis with no active cooling, and couldn't be happier for how stable and problem-free these things are.

The system is:

i815E microATX motherboard with all unnecessary peripherals (COM, LPT, Audio) turned off;
Celeron (Coppermine) 800, frequently overclocked to 1066 Mhz via FSB @133;
Geforce2 MX 32MB, sometimes swapped with a ~30W Geforce GT 610 PCI;
ES1938S soundcard with Dreamblaster S2
1 x 80mm 1400 RPM CPU/Case fan from Noctua;
1 x 512MB SDRAM stick;
2 x SD Card > CF Card > IDE adapters;
2 x USB devices - a Wi-Fi network card and a flash drive;
DVD-ROM (IDE) connected rarely for OS installation and partition management.

I imagine the real deal picoPSU should be even better at long-term abuse.

I'm trying to get this chinese PSU to power up any of my 2 machines (Pentium 4 and Cyrix MII 233MHz).
This is the one I got:

https://www.ebay.ca/itm/263087650726

It's supposed to be 180W, but apparently it's useless. On both machines I get a power blink then everything turns off. The machines don't have any cards installed. Just the on-board stuff (VGA, keyboard, Sound). Of course everything works fine on a regular PC PSU. Anyone had success with this particular model?

are you using that power brick on the picture? that says it's only 102W, I don't see that supplying enough stable power for a P4 system, and while pico psus work great for older systems their 5V rating is usually pretty low so it'll struggle with a more demanding socket 7 system.

Yes I'm using the brick that came with the PSU. Dang it! So that's two pieces that are underpowered: The PSU and the adapter. Nice 😑

Any advice on an alternative small factor or fanless ATX PSU that could work for a P4 or a Socket7?

Some more numbers on the 180W PSU I got from the seller page:

1), Input: 12V(11.4~13V)
2). Input: current: MAX.16A
3).Output ATX:180W
4).Output current +12V: 8A Max Load(15A Peak Load)
5). Output current +5V: 9A Max Load(10A Peak Load)
6).Output current +3.3V: 10A Max Load(12A Peak Load)
7).Output Current +5VSB: (and 5V some line)
😎.Output current -12V: 0.07A Max Load(0.1A Peak Load)
9).Efficiency: above 93-97%
10). Operating Temperature: -20degrees celsius - 85degrees celsius
11).Power connectors : 1x Floppy, 2x SATA, 1x 3.5" HDD
12). Dimensions: L52 X W13 X H33mm

The claim is that it can power Pentium 4 just fine. Well, that didn't work, neither on the much weaker Cyrix 233Mhz. The power brick is rated 102W, and I'm having a hard time finding a 180W brick that delivers 12V. At that wattage mostly all are giving 19V, which this PSU can't take (12V only). So I wonder for those who are using similar DC/DC PSUs, what power bricks are you using with them?

I'm using a 120W 20pin PicoPSU similar unit (I suppose not the original) with an external 5A 12v AC/DC unit on which both specs I'd not trust much cause they both seems to warm up already even with low power demand (like 20 watts); bios reading seems ok with maybe even too high voltages (+0,15 volts) beside how much bios reading can be precise.
Had to change the metal plug case connector broken during the fixing soldering another one for the main DC input but the mini-itx system works good on this config. Power demands are anyway quite low 15-20 watts around that.
I'd not trust loading 120 watts on this PSU but even less 60 watts on the AC/DC unit.

wbahnassi wrote on 2022-05-18, 12:53:

The claim is that it can power Pentium 4 just fine. Well, that didn't work, neither on the much weaker Cyrix 233Mhz. The power brick is rated 102W, and I'm having a hard time finding a 180W brick that delivers 12V. At that wattage mostly all are giving 19V, which this PSU can't take (12V only). So I wonder for those who are using similar DC/DC PSUs, what power bricks are you using with them?

At this voltage and power level you might need to look at industrial power bricks like Meanwell GSB series. Alternatively you could use enclosed AC/DC PSU and mount it inside the case.

So an update. Got me an original PICO PSU 160w from mini-box.com, and it was able to smoothly power up both Pentium 4 and Cyrix 233 machines. I haven't installed any peripherials yet, but at least this one was able to boot up, whereas the supposedly 180w one wasn't able to even boot the machines.
I'll update here once I put more load into those machines. I plan to mainly add:
* 5.25" FDD
* 3.5" FDD
* CD ROM
* CF-2-IDE as an HDD
* SB16 ASP

Aiming for a tiny footprint super-quiet MS-DOS build. One notable point, the 160w PSU was able to work fine through the 102W brick I had. I left it on for a while and didn't sense any heat or otherwise abnormal behavior.