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Can you use an ATX power supply with a mATX mobo?

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November 6, 2004 1:24:53 AM

Is it possible to use an ATX power supply with a microATX motherboard? Are all the connectors and power voltages the same or are there differences between the two?
a b V Motherboard
November 6, 2004 1:34:30 AM

Micro ATX uses ATX power. There is no "micro ATX" power supply. There are various form factors used in Micro ATX cases, including full sized (called PS-II form factor), PS-III (same mounting face as PS-II, but shorter front to back), SFX (smaller in every direction), and even TFX (smaller face than SFX but longer internally), there are even a few oddball sizes, all based on ATX.

Many discount shop-built computers use Micro ATX boards in full sized cases with full-sized power.

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November 6, 2004 10:39:24 PM

Newegg lists a number of microATX power supplies here:
http://www.newegg.com/app/ViewProduct.asp?submit=proper...

What I'd like to do is upgrade a system that I currently have. I was thinking about keeping my current case (which is from Compaq and appears to be a microATX case). Then I wanted to replace the power supply with an ATX (instead of a microATX) power supply, and also replace the motherboard with a different microATX motherboard.
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a b V Motherboard
November 6, 2004 10:58:00 PM

The problem, like I said, is that there is no size called "micro ATX" for power supplies. There are several small sizes that Micro ATX cases often use.

I had a Dell Micro ATX case that used a full sized power supply (PS-II). But most Micro ATX compaqs came with SFX or PS-III sized power supplies.

<A HREF="http://www.newegg.com/app/ViewProductDesc.asp?descripti..." target="_new">Here's Newegg's highest rated SFX power supply</A>
<A HREF="http://www.newegg.com/app/ViewProductDesc.asp?descripti..." target="_new">Here's Neweggs ONLY PS-III power supply</A>

Notice those power supplies are completely different. And Newegg list them both as "Micro ATX", proving there is no size called "micro ATX", they simply call all their small supplies by that inaccurate name.

Though your case doesn't use it, <A HREF="http://www.newegg.com/app/ViewProductDesc.asp?descripti..." target="_new">Here's a TFX power supply</A> listed under the same catagory.

You have to figure out if you have an SFX or PS-III sized power supply. If it's PS-III, we'll have to look elsewhere for a higher-capacity unit.

<font color=blue>Only a place as big as the internet could be home to a hero as big as Crashman!</font color=blue>
<font color=red>Only a place as big as the internet could be home to an ego as large as Crashman's!</font color=red>
a b V Motherboard
November 6, 2004 11:03:02 PM

By the way, there is no size called "ATX", either. PS-II is the full-sized form factor often simply refered to as ATX.

PS-II, PS-III, SFX, TFX, all are ATX power supplies. If you wanted to go with a full sized power supply, all you'd have to do is make sure it fit.

Many Micro ATX cases used PS-III power supplies, some actually had room for the longer PS-II (full sized) unit. The sticking point here is usually whether the larger supply will clear the power connector on the back of your CD-ROM drive. All you can do is measure.

It would be preferable to use a full-sized power supply, but only if you have room for it.

<font color=blue>Only a place as big as the internet could be home to a hero as big as Crashman!</font color=blue>
<font color=red>Only a place as big as the internet could be home to an ego as large as Crashman's!</font color=red>
November 6, 2004 11:55:22 PM

I think I can fit an ATX power supply in the case. I tried once....
However, I may have to choose a microATX motherboard, and I was wondering if it would work with the ATX power supply since it is different than what I got.
Also, could it be possible that my system might even be able to handle a regular ATX motherboard?
a b V Motherboard
November 7, 2004 12:19:45 AM

Once you've determined an ATX power supply fits, your concern is age: Older ATX power supplies didn't have ATX12v (aka P4) connectors, those are 4-pin square. Newer boards require them.

ATX boards are 12 inches tall and support up to 7 slots. Micro ATX boards are 9.5" tall and support up to 4 slots. The smaller boards can be used in larger cases, but the larger boards can't be used in smaller cases, so look at the number of slots the case supports.

<font color=blue>Only a place as big as the internet could be home to a hero as big as Crashman!</font color=blue>
<font color=red>Only a place as big as the internet could be home to an ego as large as Crashman's!</font color=red>
November 7, 2004 1:13:31 AM

Quote:
Once you've determined an ATX power supply fits, your concern is age: Older ATX power supplies didn't have ATX12v (aka P4) connectors, those are 4-pin square. Newer boards require them.

Both the power supply (ATX) and the motherboard (microATX) would be new, so this shouldn't be a problem right? and they should be compatable, correct?
a b V Motherboard
November 7, 2004 1:28:17 AM

Correct. ATX power supplies (including the small ones and full sized ones) have included the ATX12v connnection ever since Intel released that requirement nearly 4 years ago.

So your only concern now is what parts will fit inside your case.

<font color=blue>Only a place as big as the internet could be home to a hero as big as Crashman!</font color=blue>
<font color=red>Only a place as big as the internet could be home to an ego as large as Crashman's!</font color=red>
November 7, 2004 1:49:37 AM

Ok, thanks.... I just want to make sure nothing blows up when I plug it in. I would get a microATX power supply, however I need more power and I would like one that is quiet.
a b V Motherboard
November 7, 2004 2:15:39 AM

LMAO!

FOR THE THIRD TIME THERE IS NO SUCH THING AS A MICRO ATX POWER SUPPLY! Micro ATX cases come with MANY different power supplies, SOME COME STANDARD WITH FULL SIZED SUPPLIES!!!

<font color=blue>Only a place as big as the internet could be home to a hero as big as Crashman!</font color=blue>
<font color=red>Only a place as big as the internet could be home to an ego as large as Crashman's!</font color=red>
November 7, 2004 2:38:14 AM

Ok, sorry about that. So they are all ATX internally (or the same as ATX in terms of connections and power output) but just with different box dimensions. <- I see now this is what your first post says.

<P ID="edit"><FONT SIZE=-1><EM>Edited by KevinAr18 on 11/06/04 11:39 PM.</EM></FONT></P>
a b V Motherboard
November 7, 2004 2:56:31 AM

Exactly, use the largest power supply that fits.

<font color=blue>Only a place as big as the internet could be home to a hero as big as Crashman!</font color=blue>
<font color=red>Only a place as big as the internet could be home to an ego as large as Crashman's!</font color=red>
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