Supplying power to *lots* of ide devices ... how do I do it?

[anxman69]

Hey guys ... I'm building a server with about ... 7-8 ide harddisks. How do I go about supplying power to all of these drives? Do you know what kind of power a single drive draws? If so ... maybe we could work out the math behind the cpu/mobo/ram + 8 hds. There will be inside the case:

Athlon 750 + K7M mobo
512mb pc133 ram
1 x 1.5gb boot drive
6-7 x 80/100GB drives
1 Promise ATA100 Controller

Right now there's only a 300W PS in there supplying power for the 1.5gb + 4 x 80 gb hds. If I were to get a 450W ps with 6 molex connectors and then split off 2-3 of them, would that be appropriate? My case only fits 1 power supply unfortunately (it's one of the wonderful cases modded with lots of fans).

Let me know your suggestions so I can get this behemoth server up!

Thanks

cya l8r

 

[zephyrprime]

According to the datasheets at the Maxtor site, their D740X drives use 24watts at spinup and 12.5 watts while seeking. Their D540X (5400 rpm) uses 23.7W at spinup and 5.2 while seeking.

They only use the 12V and 5V lines. I believe that all devices that connect through the 4 pin connectors only use 12V and 5V. If you need a lot of power for your drives, you could try the "2 power supplies trick" where you use a separate power supply for the drives. I've read on another anandtech thread that using 2 power supplies actually works. (But if it doesn't, please don't sue me.

 

[anxman69]

Yeah, I also read that on their site. How much power do you think my motherboard / cpu / ram / ide controller consume?

cya l8r

 

[chizow]

You might be able to get away with 1 PSU, as the Athlon CPU and mobo draw power from the 3.3V and 5V rail, freeing up the 12V for molex devices. I'm using a ton of stuff off the molex connectors with lotsa splits and I'm doing fine with a solid OC. My 12V rail is still at 12.30-12.35V.

Here's a quick rundown of whats feeding off my molex connectors:

4x Sunon 80mm fans
2x 7200rpm HD's
2x CD/RW/DVD drives
1x V5 PCI
1x floppy drive
1x Enermax Drive cooler (3x40mm fans)
1x Slot cooler

Exact models are in my sig. You should check out Insane3d's sig for a completely loaded out system. He's got like 2x as much going on in his case.

As for the 2 PSU trick...it works fine. I hooked up my old 300W Enlight to some fans at first to see what my readings were, but I always leave my computer on and 2 PSU's would probably mean a noticeable increase in my power usage hehe.

Chiz

 

[FlowerMan]

24Wx8 ~ 200W

AMD CPU ~ 60W+

Plus whatever your fans take. I suggest getting a 400W+ PS or joining 2 300's. I joined my 431 with a 330

 

[MrChicken]

A guy at work and I were talkng about this.

We decided that case makers should go a standard of using external supplies with a universal connector and a run a power bus through the ssytem. This way the case makers could run a line to every drive bay and clear up the power mess in the case and the power supplies would be external to the system and you wouldnt have to cool it as heavily.

The spot where the supply was could be used for extra drive storage or cooling, etc...

It might be ugly to have that seperate supply, but I think that for guys that run these big "mid-towers" and "full-towers" that wouldnt be an issue, and the pc's that dont need 350-500+ worth of power supplies could keep using the internal supplies.

Second to that I would like to see the case maker run an internal power bus and the internal supply would just connect to the harness, instead of the harness coming out of the supply.

 

[Jeff7]

Something came to mind about some power supplies that can start drives one at a time to avoid the extreme current draw of lots of drives spinning up at once. I really don't have anymore info; it just came to mind that such a thing does exist.

 

[Smbu]

Well, I know a lot(I'm not sure if all of them do) allow you to set the jumper, so they stagger spin at start up and don't cause a power overload by all starting up at the same time. As I was looking at the jumper setup for my Quantum Atlas 10K II, I saw 2 jumper that would be useful. I'm not sure if IDE drives have the same ability, or not.


<< DS - Delay Spin
This will cause the drive to not spin unless it receives a start unit command from a SCSI host. Most SCSI host adapters have the start unit command enabled by default in their BIOS. Enabling Delay Spin is only necessary when you are starting multiple SCSI devices at power on.

SS - Stagger Spin
This option works in conjunction when the DS jumper is installed on the drive. It will allow each device to start (spin up) at pre-determined, staggered intervals when a START UNIT command is sent by the host adapter. This is useful when operating multiple devices on the same SCSI bus (helps prevent power supply overload caused by multiple devices attempting to start concurrently). Current host adapters usually offer a START/SPOP UNIT command enable or disable. >>