Hardrives and power

Calumetbud · Feb 14, 2004, 11:35 PM

I have 3 hard drives and 4 drives: will the xtra hdd's take away any power if there not in use. I use 1 for my operating software,and 1 for my files. the other 2 is only for storage. Running a 400 watt atx p/s.

asus a7n8x/2600+ barton 512 corsair ram

Necrosis · Feb 15, 2004, 01:34 AM

Yes because they still have to keep spinning while their on.

Matth · Feb 15, 2004, 07:08 PM

They use LESS power in idle than busy, but unless they are being powered down by the system, or have a selectable low speed idle (an option on some IBM/HGST drives), it's the normal standing power level - they use MORE power during maximum seek activity.

With all those drive motors, the 12v rail is going to be the critical one - if it was going to choke, it would be during spin-up.

Necrosis · Feb 15, 2004, 07:14 PM

Another question is what are the other 4 drives?

Calumetbud · Feb 21, 2004, 03:41 PM

i have 3 hdd's one i have partitioned with my OS on one of the drives and the files on the bigger partition, makes it ez to reinstall windows without losing my files

Zardon · Feb 21, 2004, 04:03 PM

are you asking because you are experiencing problems or are you just curious? whats your rails reading?

swimtech · Feb 22, 2004, 05:15 PM

From matth:
With all those drive motors, the 12v rail is going to be the critical one - if it was going to choke, it would be during spin-up.

That's what is critical, the hard drives do use power while idling too though...
Weirdly enough, the CPU's juice is derived from the 12v rail as well, so there's a big draw at startup on the 12v rail then.

Vampyromaniac · Feb 22, 2004, 06:40 PM

Actually, the CPU is powered by the +3.3v rail

swimtech · Feb 23, 2004, 02:28 PM

Quote:

Originally posted by Vampyromaniac
Actually, the CPU is powered by the +3.3v rail

Admittedly I was working from memory, and I was pretty sure I had seen a chart in a respected publication (Maximum PC) that noted modern CPU's ran on the 12v rail. At first, it didn't make sense to me ("weirdly enough"- my previous post), but they're a picky bunch (and so are we!).

I looked at the chart again this am, and it does note 10 amps being drawn from the 12v rail using a 3.0Ghz CPU. Let's look into this Vampyromaniac, each of us, and get some more details - OK?

Edit: found this while hunting for something else, it shows the devices, power draw in watts, and the rail it draws from. Sure helped me...

High-wattage AGP card
20 - 50W +3.3V
Average PCI card
5W +5V
Cached PCI SCSI controller card
20-25W +3.3V and +5V
Floppy drive
5W +5V
10/100 NIC
4W +3.3V
Typical Atapi CD-ROM
10 - 25W +5V and +12V
Typical Atapi DVD-ROM
10 - 25W +5V and +12V
Typical SCSI CD-R/RW
20W +5V and +12V
SCSI CD-ROM
12W +5V and +12V
RAM
8W per 128MB +3.3V
Ultra2 SCSI PCI card
5W +3.3V and +5V
5400rpm IDE hard drive
5 - 10W +5V and +12V
7200rpm IDE hard drive
5 - 15W +5V and +12V
7200rpm Ultra2 SCSI hard drive
24W +5V and +12V
10,000rpm SCSI drive
10 - 40W +5V and +12V
Motherboard (without CPU or RAM)
20 - 30W +3.3V and +5V
Typical Pentium II
30W +5V
1GHz and up Pentium III
34W +5V
Typical Pentium 4
65W +12V
Typical AMD Athlon
70W +12V

The chart is available in more readable form at www.thetechboard.com/tutorials/atx.php

Vampyromaniac · Feb 23, 2004, 08:00 PM

Interesting

I always thought it was the 3.3. I remember because when I first was planning to buy my Athlon XP, I was reading to see what power supplt I should buy, and I came across one that said for XP's, buyers should make note that the 3.3v rail supplies plenty of watts. It was on Anandtech I think, but it's porbably buried in the site somewhere.

swimtech · Feb 23, 2004, 10:39 PM

Yeah, very interesting. But you know it makes sense too. In order to get the necessary amps out of the supply to the CPU (primary draw then...) and drive motors (for Calumetbud that's SEVEN drives - whew!), the voltage would have to stay high for as long as possible to move freely across small wires or traces (at a relatively low amperage).

After it is regulated to roughly 1.6v (with some losses in the process) the amps increase and the need for large wires or traces from the regulator to the CPU become necessary. It keeps the amount of copper needed for traces to a minimum.

Calumetbud, from the chart, a hard drive at idle looks to draw .3 to .5 amps, and 1.3 or so at maximum load (startup).

Edit: I would guess the caution for XP's sucking the 3.3v line might be in consideration of the memory and the AGP card.

Feb 14, 2004, 11:35 PM	#1
Calumetbud HardwareHeaven Junior Member Join Date: Jun 2003 Posts: 96 Rep Power: 0	Hardrives and power I have 3 hard drives and 4 drives: will the xtra hdd's take away any power if there not in use. I use 1 for my operating software,and 1 for my files. the other 2 is only for storage. Running a 400 watt atx p/s. asus a7n8x/2600+ barton 512 corsair ram

Feb 22, 2004, 05:15 PM	#7
swimtech HardwareHeaven Extreme Member Join Date: May 2002 Location: North Carolina Posts: 4,040 Rep Power: 122 System Specs	From matth: With all those drive motors, the 12v rail is going to be the critical one - if it was going to choke, it would be during spin-up. That's what is critical, the hard drives do use power while idling too though... Weirdly enough, the CPU's juice is derived from the 12v rail as well, so there's a big draw at startup on the 12v rail then. __________________ It's not so much getting your way that matters or not - what matters is how you go about getting it.

Feb 22, 2004, 06:40 PM	#8
Vampyromaniac confutatis maledictis Join Date: May 2002 Location: somewhere dark Posts: 5,974 Rep Power: 74 System Specs	Actually, the CPU is powered by the +3.3v rail __________________ *Digitalis 3.3* Athlon 64 3000 // ASUS K8V SE Deluxe // 1024MB PC3200 (2-2-2-10 1T) ATI All-In-Wonder 9700 Pro // 20" Dell 2005FPW (DVI) M-Audio Revo 7.1 + Philips Acoustic Edge // Klipsch ProMedia 2.1 320/16 Western Digital WD3200KS + 120/8 Seagate 7200.7 NEC ND-3550A 16x DVD±RW + Lite-On 52x24x CD-RW Antec Sonata case // 480W Antec TruePower personal bests \|\| Aq'3: 46796 \| 3D'01: 20461 \| 3D'03: 6336 \| 3D'05: 2677 \| PC'04: 4605 \| PC'02: 7691,9092,1250

Feb 23, 2004, 08:00 PM	#10
Vampyromaniac confutatis maledictis Join Date: May 2002 Location: somewhere dark Posts: 5,974 Rep Power: 74 System Specs	Interesting I always thought it was the 3.3. I remember because when I first was planning to buy my Athlon XP, I was reading to see what power supplt I should buy, and I came across one that said for XP's, buyers should make note that the 3.3v rail supplies plenty of watts. It was on Anandtech I think, but it's porbably buried in the site somewhere. __________________ *Digitalis 3.3* Athlon 64 3000 // ASUS K8V SE Deluxe // 1024MB PC3200 (2-2-2-10 1T) ATI All-In-Wonder 9700 Pro // 20" Dell 2005FPW (DVI) M-Audio Revo 7.1 + Philips Acoustic Edge // Klipsch ProMedia 2.1 320/16 Western Digital WD3200KS + 120/8 Seagate 7200.7 NEC ND-3550A 16x DVD±RW + Lite-On 52x24x CD-RW Antec Sonata case // 480W Antec TruePower personal bests \|\| Aq'3: 46796 \| 3D'01: 20461 \| 3D'03: 6336 \| 3D'05: 2677 \| PC'04: 4605 \| PC'02: 7691,9092,1250

Feb 23, 2004, 10:39 PM	#11
swimtech HardwareHeaven Extreme Member Join Date: May 2002 Location: North Carolina Posts: 4,040 Rep Power: 122 System Specs	Yeah, very interesting. But you know it makes sense too. In order to get the necessary amps out of the supply to the CPU (primary draw then...) and drive motors (for Calumetbud that's SEVEN drives - whew!), the voltage would have to stay high for as long as possible to move freely across small wires or traces (at a relatively low amperage). After it is regulated to roughly 1.6v (with some losses in the process) the amps increase and the need for large wires or traces from the regulator to the CPU become necessary. It keeps the amount of copper needed for traces to a minimum. Calumetbud, from the chart, a hard drive at idle looks to draw .3 to .5 amps, and 1.3 or so at maximum load (startup). Edit: I would guess the caution for XP's sucking the 3.3v line might be in consideration of the memory and the AGP card. __________________ It's not so much getting your way that matters or not - what matters is how you go about getting it. Last edited by swimtech; Feb 23, 2004 at 10:50 PM.

Feb 15, 2004, 01:34 AM	#2
Necrosis HardwareHeaven Extreme Member Join Date: May 2002 Location: Ohio Posts: 8,838 Rep Power: 129 System Specs	Yes because they still have to keep spinning while their on.

Feb 15, 2004, 07:08 PM	#3
Matth Flash Banner Hater Join Date: Jun 2002 Location: UK Posts: 3,410 Rep Power: 91 System Specs	They use LESS power in idle than busy, but unless they are being powered down by the system, or have a selectable low speed idle (an option on some IBM/HGST drives), it's the normal standing power level - they use MORE power during maximum seek activity. With all those drive motors, the 12v rail is going to be the critical one - if it was going to choke, it would be during spin-up.

Feb 15, 2004, 07:14 PM	#4
Necrosis HardwareHeaven Extreme Member Join Date: May 2002 Location: Ohio Posts: 8,838 Rep Power: 129 System Specs	Another question is what are the other 4 drives?

Feb 21, 2004, 03:41 PM	Thread Starter #5
Calumetbud HardwareHeaven Junior Member Join Date: Jun 2003 Posts: 96 Rep Power: 0	i have 3 hdd's one i have partitioned with my OS on one of the drives and the files on the bigger partition, makes it ez to reinstall windows without losing my files

Feb 21, 2004, 04:03 PM	#6
Zardon DriverHeaven Founder Join Date: May 2002 Posts: 32,480 Rep Power: 177	are you asking because you are experiencing problems or are you just curious? whats your rails reading?