Hatta wrote:

Is it better to try and source a vintage power supply for these machines? Would a modern PSU with 25A on 5V be OK? Should I try and repair my current PSU? For all I know it may just need a recap. Would it be crazy to use the 12V supply with a voltage regulator?

Sourcing a good vintage PSU can be problematic, used units may have broken caps and fans, especially if they were produced during the "capacitor plague" years (early 2000s).
On my KT7A machine I use an Enermax 465W unit which boasts a whopping 44A on +5V 😁, but even that one had to be modded to stop the +5V rail from sagging under load.

You mentioned you have an Antec Basiq 350 PSU available, how many amps does that one deliver on +5V? If it's 25A, it might be worth a try.

As a nice baseline for PSUs to power old ATX motherboards, these are the ratings of a classic PC Power & Cooling Turbocool 300W.

+5V @ 30A
+12V @ 12A
-5V @ 0.3A
-12V @ 1A
+3.3V @ 14A
+5VSB @ 850mA
+5 & +3.3<150W

http://web.archive.org/web/20000229212556/htt … ndex_hp_atx.htm

I have yet to have problems using modern 12v oriented PSUs though. But some of the cheapies are surely too weak for Athlon and early P4 systems. P3 is lower power and not much of a concern.

From what I can gather, the Antec Basiq BP350 has 20A on the 5V.

http://www.newegg.com/Product/Product.aspx?It … N82E16817371003

Do you all think that would be OK with the Athlon 1400, Ti4600, and two Voodoo 2 cards?

KT7AGuy wrote:

From what I can gather, the Antec Basiq BP350 has 20A on the 5V.

http://www.newegg.com/Product/Product.aspx?It … N82E16817371003

Do you all think that would be OK with the Athlon 1400, Ti4600, and two Voodoo 2 cards?

Why not have a look at this one?
http://www.newegg.com/Product/Product.aspx?It … N82E16817103013

Dang, it's so hard to find PSU's with decent 5v lines these days!
20A on the 5v line is very little for an Athlon 1400, these CPU's eat at least 70W or so.

Edit: Forget these powersupplies. I checked the specs from their respective manufacturers, and both of them are 25A at 5V. Argh. 😠

At risk of getting too far off topic, what are the symptoms of insufficient voltage? Looking at my boxes I have a few with 30A on the 5v line, including a Phenom II X4, Athlon XP, dual Athlon MP, and a Prescott. Never had stability issues so far, but that MP hasn't been used much... just wondering if I have trouble brewing.

^
yes, it is probably a good idea to make a new thread on this whole PSU/power req thread esp on the +5V line for earlier ATX systems (esp. Socket A).

@ratfink,
That depends on your motherboards and combination of hardware for each system, so you gotta figure out the components yourself -- but your Phenom II and Prescott most likely are "12V heavy" (a quick check is to look whether the board has/is using 2x2/4pin ATX12V connector, but please consult your manuals).

For anyone else concerned, this older Power Supply FAQ from jonnyguru may be helpful:
http://www.jonnyguru.com/forums/showthread.php?t=1036

@Hatta,
As I'm using a Corsair (HX850, which maxes at 25A on +5V), I got curious and checked other current Corsair models, and I found that most give 25A tops on +5V, including the TX650/750/850 V2, though I found some sites still list them using spec from older version, so be careful on that.

@KT7AGuy,
It's hard to find exact max TDP numbers on NVIDIA cards prior to GF 7/8 gen, but here are some numbers I get (in typical power draw, not max burn):
Geforce FX 5950 Ultra: 74 W
Geforce FX 5900 Ultra: 59 W
Geforce FX 5900: (should be slightly above the XT due to higher memory clock)
Geforce FX 5900 XT: 35 W

for comparison:
Geforce 4 Ti: 40W (though not clear which model)
Geforce 6800 Ultra: 72 W
Geforce 6800 GT/GS: 55 W
Radeon 9800 XT: 60 W
Radeon 9800 Pro: 47 W

So if you approx Athlon 1400 (~72 W full load) + GF 4 Ti (~40W typical) that's already 112 W, so you may be stressing that PSU already. EDIT: see following posts.

These video cards draw from 12v so 5v shouldn't be overloaded. The fact that these cards use mainly 12v also brings up the problem with the weak 12v output of old PSUs.

Voodoo2 SLI is probably like 20W? These cards don't even have heatsinks so there's not a lot of power going through there.

A quality PSU will just shut down if it's overloaded. Cheap ones can blow up. Let us know what happens. 😁

I thought that after the end of the P3 era that cpu vrm designs had moved over to using the 12v rail but I learn something new everyday. I do know about the design of some multi rail power supplies. The 5V rail and usual one of more 12V rails is shared on some units so one couldn't just load it down to its max rating without there being some sag on the volts. I got only one good 5V rail unit all though I personally regard it as junk, a Thermaltake Purpower 500 ( http://www.newegg.com/Product/Product.aspx?It … N82E16817153052 ) as it gets rather hot on my Athlon rig. All one can count on a high quality modern unit is being able to push it beyond its rated specs provided the 12v wasn't pushed hard and ocp doesn't kick in till a little later. I have been saving junk supplies from this era but I keep procrastinating about recapping them.

EDIT: Not all Socket A boards have the cpu drawing power from the 5V Rail, the ones that have the 4Pin eps connector draw from off the 12v rail instead just like many 478 and 775 board ect.

Examples, http://www.amazon.com/PCCHIPS-M863G-Motherboa … ds=Socket+A+462

http://www.amazon.com/Micro-Star-MSI-K7N2-Del … ds=Socket+A+462

http://www.newegg.com/Product/Product.aspx?It … N82E16813135148

swaaye wrote:

These video cards draw from 12v so 5v shouldn't be overloaded. The fact that these cards use mainly 12v also brings up the problem with the weak 12v output of old PSUs.

Oh right, I got that backward, yes the Geforce FX 5900/5950 series will use power mostly from power supply's 12V rail through a Molex plug so it should be OK. It is the GF 4 Ti 4600 that draws power from the AGP slot --> motherboard. But then it's likely split between 3.3V, 5V and 12V (not sure about the exact AGP spec, but mostly from 3.3V I think).

Voodoo2s are 5V PCI cards, though AFAIK. Probably at 10-15W per card at full load.

A quality PSU will just shut down if it's overloaded. Cheap ones can blow up. Let us know what happens. 😁

Good idea, I suggest overclocking the beastie Athlon. Hehe, but honestly, since it's an Antec I think it will survive working to its limit for some time.

I learned about the +5V issue early because I had to administer a lab full of 1.0-1.4 GHz Athlons at university. The dealer shipped them with cheap "300W" PSUs that came included with the cases, needless to say they were rather unstable machines, and most of the PSUs were dead after just a few months. Back then, it was rather difficult finding decent replacements, as most PSUs on the market were the same crap. I remember replacing most of them with Enermax 365W units, and the problems were gone (at least for some time, until the capacitor plague kicked in and mainboard caps were going off like popcorn).

nforce4max wrote:

Not all Socket A boards have the cpu drawing power from the 5V Rail, the ones that have the 4Pin eps connector draw from off the 12v rail instead just like many 478 and 775 board ect.

Yup that started around 2002 with nForce2/KT400/etc.

Check this one out:

StarTech ATX2POWER450 450W ATX12V Ver2.01 Power Supply

http://www.newegg.com/Product/Product.aspx?It … N82E16817707078

It looks pretty good for our needs. It's the only new PSU I can find with greater than 30A on the 5V. What do you all think?

I use a StarTech AT PSU with my old P200 system and I've never had an issue with it. Of course, it is literally the only AT PSU that I could still find, so I didn't have much choice...

KT7AGuy wrote:

Check this one out: […]
Show full quote

Check this one out:

StarTech ATX2POWER450 450W ATX12V Ver2.01 Power Supply

http://www.newegg.com/Product/Product.aspx?It … N82E16817707078

It looks pretty good for our needs. It's the only new PSU I can find with greater than 30A on the 5V. What do you all think?

I use a StarTech AT PSU with my old P200 system and I've never had an issue with it. Of course, it is literally the only AT PSU that I could still find, so I didn't have much choice...

I can't say much about it till I see some pics of the unit's board.

EDIT: I checked my scrap heap and found a 431w Enermax unit that has 44amps on the 5V rail but the sad part it needs new caps. 10v 4700uf 😒

I also found this Rosewill PSU that supposedly provides 55A on the 5V:

Rosewill RP600V2-S-SL 600W ATX12V v2.01 SLI Ready Power Supply
http://www.newegg.com/Product/Product.aspx?It … N82E16817182032

Unlike the StarTech unit, this one is backed up with some positive reviews.

Would there be a hazard in using a modern 600W PSU with my old KT7A? If not, this one is looking like a winner to power the Athlon 1400 and 5900 Ultra.

Another question:
What risk is there in just buying an old PSU on eBay with decent amps on the 5V, and then having it recapped? Would recapping a PSU essentially "refurb" the unit and prepare it for years of new service?

KT7AGuy wrote:

I also found this Rosewill PSU that supposedly provides 55A on the 5V: […]
Show full quote

I also found this Rosewill PSU that supposedly provides 55A on the 5V:

Rosewill RP600V2-S-SL 600W ATX12V v2.01 SLI Ready Power Supply
http://www.newegg.com/Product/Product.aspx?It … N82E16817182032

Unlike the StarTech unit, this one is backed up with some positive reviews.

Would there be a hazard in using a modern 600W PSU with my old KT7A? If not, this one is looking like a winner to power the Athlon 1400 and 5900 Ultra.

Another question:
What risk is there in just buying an old PSU on eBay with decent amps on the 5V, and then having it recapped? Would recapping a PSU essentially "refurb" the unit and prepare it for years of new service?

Nah, there's not much hazard in running a modern PSU with older hardware, you just really have to make sure the unit can actually push the wattage and amps it's rated for.

As to whether recapping would refurb an ebay unit and get you some good years of service, that would depend on what you replaced the existing caps with and how good a job you did replacing them. Then there's the design of the PSU itself, if the design wasn't that great to begin with, recapping isn't really going to get you much out of the thing.

The problem with getting old power supplies is that it's pretty much a crap shoot on what you're getting. The power supply could be a reputable brand and you might still get a unit with bad caps simply because of age/abuse or because it might have been built back during the capacitor plague years. I got an old TTGI 520W for my Xeon rig because it had a 6-pin aux connector I needed, but the PSU I got had multiple bulged caps and a few that had actually leaked/vented. Apparently it tested good for the seller, but even so, that thing probably would have failed soon after installation. I supposed I could recap it, but the internal design is such that doing so would be a real pain. It would probably be good to go with a recapping though. Luckily I was able to get a refund for the thing. I may just amputate the 6-pin aux and splice it into the 20-pin extension that came with the PSU.

i would just recap it and go with it.
just pay attention to what youre doing and get some good low esr caps.
@m1919 what caps can you get a hold on.

I'm tempted to just use a Voodoo 5 5500 instead and hope to avoid the PSU issues. So now the question is:

Will the Antec Basiq 350W PSU with 20A on the 5V be enough for an Athlon 1400 and an AGP Voodoo 5 5500?

Thanks!

KT7AGuy wrote:

I'm tempted to just use a Voodoo 5 5500 instead and hope to avoid the PSU issues. So now the question is:

Will the Antec Basiq 350W PSU with 20A on the 5V be enough for an Athlon 1400 and an AGP Voodoo 5 5500?

Thanks!

Yes, I was using XP 2800 and a 6800GT on a 300W PSU. My opinion is that people are worrying too much about PSU power. Never had or heard anyone have any real problems with it.