VOGONS


First post, by tunertom

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Hey guys,

So I've noticed there is some difficulty sometimes with choosing an appropriate power supply for said socket earlier systems requiring a (monster by todays standards) 5v and 3.3v rail.

https://www.ebay.co.uk/itm/203608026383
12V/24V to 5V 40A 200W Step Down DC/DC Power Converter

now I was thinking of using this in conjunction with a modern power supply, to my understanding, it will connect to the 12v rail, stepping down to 5v and boost the 5v rail by a maximum value of 40 extra amps

I can't see any problem with this, since it will be a common ground, but does anyone else see any issue that might arise?

Reply 1 of 9, by BitWrangler

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One thing that occurs to me is whether the startup time is fast enough such that the board doesn't go "nope" before it's delivering 5V.

Unicorn herding operations are proceeding, but all the totes of hens teeth and barrels of rocking horse poop give them plenty of hiding spots.

Reply 2 of 9, by cyclone3d

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I think it should be fine as far as the speed goes. It is just a buck converter from the description.

If it did have an issue with starting up I would think that a push of the reset button on the computer would take care of it.

The only thing I would worry about is what would happen if the converter shorted out and decided to supply up to the input voltage.

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Reply 3 of 9, by tunertom

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The 2 main power hungry components I will be using will be the 423 socket 2.0ghz P4 + an FX5950 Ultra.

Is anyone experienced enough to tell me what rail the fx5950u is likely to draw from? Seen mixed answers online

Reply 6 of 9, by cyclone3d

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tunertom wrote on 2022-01-31, 21:27:

The 2 main power hungry components I will be using will be the 423 socket 2.0ghz P4 + an FX5950 Ultra.

Is anyone experienced enough to tell me what rail the fx5950u is likely to draw from? Seen mixed answers online

I have an industrial setup with and Intel Pentium 4 3.2 that I tested my FX5950U in and a Seasonic SS-500ET is plenty. Has 24A on the 5v rail.

You also have to remember that the power requirements were specc'd for the lowest possible quality power supplies available at the time.

[H]ardOcp did some tests of low tier PSUs a few years ago and found that a lot of them would blow with around 50% or so of their rated wattage.

Most good newer PSUs are also rated for continuos load and not a max temporary load like the crappy ones have always been.

Yamaha YMF modified setupds and drivers
Yamaha XG resource repository - updated November 27, 2018
Yamaha YMF7x4 Guide
AW744L II - YMF744 - AOpen Cobra Sound Card - Install SB-Link Header

Reply 7 of 9, by tunertom

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cyclone3d wrote on 2022-02-01, 00:06:
I have an industrial setup with and Intel Pentium 4 3.2 that I tested my FX5950U in and a Seasonic SS-500ET is plenty. Has 24A o […]
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tunertom wrote on 2022-01-31, 21:27:

The 2 main power hungry components I will be using will be the 423 socket 2.0ghz P4 + an FX5950 Ultra.

Is anyone experienced enough to tell me what rail the fx5950u is likely to draw from? Seen mixed answers online

I have an industrial setup with and Intel Pentium 4 3.2 that I tested my FX5950U in and a Seasonic SS-500ET is plenty. Has 24A on the 5v rail.

You also have to remember that the power requirements were specc'd for the lowest possible quality power supplies available at the time.

[H]ardOcp did some tests of low tier PSUs a few years ago and found that a lot of them would blow with around 50% or so of their rated wattage.

Most good newer PSUs are also rated for continuos load and not a max temporary load like the crappy ones have always been.

I appreciate your response, but your 3.2GHz P4 is likely socket 478, so within the 12v CPU power draw era

On my ABIT TH7-RAID board with 423 socketed 2GHz P4 its still nailing the 5v rail

So adding a potentially 5v sucking GPU to an already 5v hungry CPU, just wanted to make sure I had my bottom well protected, seeing how rare and expensive my particular parts have become

Reply 8 of 9, by cyclone3d

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I can always test with a 423 setup. Just haven't had a 423 board until recently.

If the board I have works, I can also test with a 478 CPU as I have an adapter on the way

Yamaha YMF modified setupds and drivers
Yamaha XG resource repository - updated November 27, 2018
Yamaha YMF7x4 Guide
AW744L II - YMF744 - AOpen Cobra Sound Card - Install SB-Link Header

Reply 9 of 9, by pixel_workbench

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What is the problem with using a modern PSU that provides 150W on the 5v rail? A good modern power supply uses DC-DC conversion to get 5v and 3.3v from the 12v rail, so heavy 5v loads should not cause the other voltages to go out of spec.

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