What Size Power Supply?

[MarcD]

I want to get a nice quiet power supply, but I don't know which size to get. How do I determine the power needs of each system component? I have:

3 7200 rpm HDDs
1 CD-ROM drive
1 CD-RW drive
1 DAT drive
1 AGP video card
1 PCI SCSI controller
1 10/100 NIC
1 AMD Athlon 1.3GHz CPU
256 MB PC100

As for which power supply to get, I've seen:

Q Technology 300W (26dB) -- $95
PC Power and Cooling 400W (38dB) -- $179

My hunch is that I need more than 300W, but I am loath to spend nearly $200 on a power supply. Are there any others I should be looking at?

Thanks.

Marc

[iisbob]

i know they make a 350watt, just not sure where i saw it. But i'd go ahead for the 400, athlons are extremely power hungry and with that many periphials i'd rather spend $200 now than ahve to spend up to $1000 replacing them if they all failed! This is a case where i think i'd err on the " pay a little more now "than " pay a lot more later " http://www.PCGuide.com/ubb/tongue.gif

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iisbob
"Soap and education are not as sudden as a massacre, but they are more deadly in the long run."

[Rick]

MarcD

I Have the PC Power 425 ( No Silencer ) at 44db.
I can not hear the power supply fan over the CPU HS Fan.(delta 7200)

Depending on what HSF you have with that 1.3 You may find the same thing happening on your system

You can add the Watt requirements for each item in your list and add everything together.
Assuming the 300watt suggested power supply would take in account for the M/B 1 HHD 1 CD and 1 other drive. Plus a safe margin for error.
You may find your safe with the 300. But with little or no reserve/margin for error.
IMHO the 400 up front is the way to go.

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To ERR is HUMAN
To REALLY screw things UP, YOU NEED a COMPUTER !

[yawningdog]

The wattage rating on a power supply is not nearly as important as the quality of the device. With that kind of bank tied up in hardware, I would definitely spend the extra cash. A $200.00 300w power supply is a better idea than a $150.00 400w power supply. It's important that a power supply be able to smooth out all the spikes, fuzz, noise, glitches, and drops which are precipitated by the computer itself as it hums and buzzes along during it's normal everyday chores. Not to mention the electronic crud which floods your machine through your power, modem, and network connections.

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He thrusts his fists against the posts but still insists he sees the ghosts.

[ranchdog]

MarcD -- Pretty descent rule of thumb method is to add up your power using devices, devide that number by three, and multiply by 100. Then you will have a ballpark figure of the size you'll need (in Watts) with a little to spare. Smile.

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"Lemmee Fix That Thing......."
-Beauty is only a light switch away.-

[mjc]

I know that this one is a couple of days old but take a look a the Enermax EG365 (http://www.enermax.com.tw/products/eg-365p-vefca.htm#s), quiet, powerful and 8 connectors. It has feature that I saw listed as disadvantage in one review...long cables. They also have a 400W version.

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mjc
Links list:Computer Links (http://www.fortunecity.com/skyscraper/highrise/11/index.htm)

Celts are the men that heaven made mad, For all their battles are merry and their songs are all sad.

[MarcD]

Thank you all for the information, particularly for the quality power supplies. Ranchdog gave a rule of thumb to estimate power needs, but I would think there should be some source that says that 7200 rpm HDDs generally consume X watts of power, and CD-ROM drives usually consume Y watts. I'm surprised that drive specifications don't seem to mention power consumption. Thanks again.

[mjc]

They do, but usually you have go through the tech specs on the drive manufactuer's website...

Also the formula is Power=Volts x Amps (W = VA)...18W = 12V x 1.5A.


Seagate for example: 30GB 7200 RPM

Typical Current (12VDC +/- 10%) 0.54 amps
Startup Current (12VDC +/- 10%) 2.4 amps
Typical Current (5VDC +/- 5%) 0.62 amps
Startup Current (5VDC +/- 5%) 0.8 amps



Which translates to about 25W at startup and 6.5W running, most others should be about the same.

A Samsung DVD/CD combo drive uses 1.5A (18W)max.

TEAC 12x10x32 CD-RW uses about 1.8A (21.6W) during a write operation.

I haven't seen a nice neat table with typical power requirements for drives...I guess I'll just make one and stick it on my site... http://www.PCGuide.com/ubb/biggrin.gif

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mjc
Links list:Computer Links (http://www.fortunecity.com/skyscraper/highrise/11/index.htm)

Celts are the men that heaven made mad, For all their battles are merry and their songs are all sad.


[This message has been edited by mjc (edited 07-19-2001).]

[ranchdog]

http://www.PCGuide.com/ubb/wink.gif Saw something interesting at AMD. Power draw by CPU's.......1.2gig T-Bird 66WATTS. 1gig T-Bird 54Watts. 850Duron 37Watts. Wonder if that's why the lights go dim when I stoke her up? But the proof is in the pudding. Don't go chincy on a power supply!
I'll never buy a PSU unless it's approved by AMD.
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"Lemmee Fix That Thing......."
-Beauty is only a light switch away.-

[This message has been edited by ranchdog (edited 07-19-2001).]

[Bailey]

I'm partial to the Enermax myself. Here (http://www.directron.com/eg451pve.html) is the 430W version for under $100.

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"Ooooh, They have the
internet on computers now!" - Homer Simpson (http://asf.allwavs.com/wav4/Simpsons/inetcptr.wav)

[nimnorf2]

Hey Bailey,
Now ya all are talkin'. Found that Enermax 431 on Pricewatch for $91 including shipping.

MarcD, I saw some other 400 watt Power Supplies for much less. I thought $200 was a bit much. If you go to AMD.com (maybe you'll have to search through Google,) they have a pretty exhaustive list of all the power supplies that are Athlon approved. I bet you can find one for under $70.00.
Good luck to ya.