Pico Psu PW-200-M and a lot of GP drives?

XS Janus · Post by **XS Janus** » Thu Apr 24, 2008 2:44 pm

I currently own a 120W version and I remember when I played around with it that I managed to power up a low power config and 4x3.5" regular old school HDDs.

Being that PW-200-M Pico is 200W capable how many of the new GP drives do you guys think this one can handle?

One more thing if I try and over load the Pico by adding drives one by one what will happen when I reach its threshold?

bexx · Post by **bexx** » Sun Apr 27, 2008 11:30 am

Well it really depends on what system you have connected. If you check the drive specs the 5V rail is likely to become the weak link.

12 VDC
Read/Write 340 mA
Idle 254 mA
Standby 6 mA
Sleep 6 mA
5 VDC
Read/Write 675 mA
Idle 195 mA
Standby 180 mA
Sleep 180 mA

If you want to build for worst case:
12v = 340mA (4.08Watts)
5v = 675mA (3.375Watts)

Here is the bad news basically:

The GP drives, compared to regular drives, draw less power on 12v rail and about the same amount of power on 5v rail.

Comparing the 120watt Pico to a 200watt the 12v rail is greatly raised, but the 5v rail is EXACTLY the same. Both provide 6amps/30watts.

Both changes are affecting the 12v rail, neither touch the 5v really. So even by doing both you shouldn't really be able to use many more drives than you can now.

Realistically however I'm guessing you'd be surprised at how many drives you could use. Assuming these are not all in a raid array where they will all be seeking/reading at the exact same time you will rarely hit the worst case... and even when this does happen... both PSUs can peak to ~10 amps for brief moments.

Anyways I can't really answer your question, but this will push it up and maybe someone else can... though i'm guessing the only real answer will come from a dc clamp meter and some experimenting.

xan_user · Post by **xan_user** » Sun Apr 27, 2008 8:42 pm

I think the power draw is much higher during spinup at boot then during use and at idle. While the pico may have the power to run the drives after spinup, i dont think it will start more than a few at a time.

XS Janus · Post by **XS Janus** » Thu May 01, 2008 3:39 pm

Thanks for posting guys.
You are right I noticed those weak 5v currents on 200W Pico definetly a weak spot for this unit.

I've found this info on this forum:

Q: spinup currents?
A:
Spinup: 2.4A(peek)@12V, 781mA@5V => 32,71W
Read/Write: 470mA@12V, 875mA@5V => 10,02W
Seek: 750mA@12V, 969mA@5V => 13,84W
Idle: 375mA@12V, 938mA@5V => 9.19W
Standby: 18mA@12V, 488mA@5V => 2.66W
Sleep: 18mA@12V, 450mA@5V => 2.48W

The answers came from WD support service but were given early in the drives lifetime (just released) so those supoport guy could be wrong.
I think those numbers are a bit off. Especialy IDLE...

I have 4 drives hooked up now (not on Pico) and they add 48W at spinup. Thats 12W each.

I have a 3ware 9650 Raid controller
I managed to enable staggered spinup on drives but it only works from windows.
BUT I can't get it to work that way on cold system start! Any ideas?

bexx · Post by **bexx** » Fri May 02, 2008 8:53 am

Those numbers seem real high... almost as though they were from a different drive. One of GP's selling features is low spinup power draw.

"I have a 3ware 9650 Raid controller
I managed to enable staggered spinup on drives but it only works from windows.
BUT I can't get it to work that way on cold system start! Any ideas?"

Problem isn't with the 3ware controller, it is the drives.

There are two (as far as I know) ways to enable staggered spinup on drives:
1. Utility. I forget who does what but I'd call up WD and ask, or maybe try dling whatever utilities you can find on their site to try to enable it.
2. SATA power connector pin 11 disconnected. This is what spec is supposed to be I think... most SATA power connectors will connect pin 11 to ground which will, according to spec, make the drive spin up immediately. You need to either somehow buy a cable that doesn't connect pin 11 or find some way to insulate/cut pin 11 in the power connector so it doesn't connect to ground.

XS Janus · Post by **XS Janus** » Fri May 02, 2008 10:24 am

Ok if I understood you correctly yoe are saying that most SATA connectors through pin 11 should power up the drives sa soon as connected to power.
That doesn't happen here as the drives can stay with power conncted and not spinning up at all.
They only spin up when I connect data cable to them.
I will call someone at WD distributour and try and see what they say.

I tried a utility from 3ware website that tries do enables WD drives from DOS and I followed a diagram provided by WD to enable PM2 as their drives come with this feature phisicaly disabled.

One other thing I should mention is that I use 5x3.5"in3x5.25 sata drive cage. But the cage is straight through sata and shouldn't be doing anything fancy.

Any thoughts on this?

bexx · Post by **bexx** » Fri May 02, 2008 8:27 pm

"That doesn't happen here as the drives can stay with power conncted and not spinning up at all.
They only spin up when I connect data cable to them.
I will call someone at WD distributour and try and see what they say. "

Wait the usual problem I get reported is drives will spin up soon as power is connected. This is caused by pin11 being connected to ground OR the drive is set to spin up soon as it gets power. The usual fix is not to use the 4pin->15pin sata connectors and use a backplane or something, or to call up drive manufactorer to get a utility to set the drive not to spin up right away and wait for controller.

If the drives are not spinning up when they get power then ignore what I said, thats how they're supposed to behave.

Spinning up soon as data cable is connected is weird... that would sound like controller problem?

The way it is supposed to work is turn system on, drives are all off, firmware for raid card loads and there is a long pause while it spins drives up one at a time, then firmware detects arrays adn continues on.

If I got time on Monday I'll try to set this up, I think we got 3ware/GP drives sittin around.

bexx · Post by **bexx** » Fri May 02, 2008 8:31 pm

http://wdc.custhelp.com/cgi-bin/wdc.cfg ... _faqid=958

Don't know if this applies to GP drives, I don't have them here. Between that and setting 3ware to OOB I think it should work :/.

XS Janus · Post by **XS Janus** » Thu May 08, 2008 11:49 pm

Hi Bexx,

Have you maybe gotten a chance to power up your 3ware and see how it behaves?

I've also sent you a PM.

THX!

bexx · Post by **bexx** » Thu May 22, 2008 3:58 pm

For anyone searching this topic WD GP drives do support staggered spinup and require pin11 to be float and not connected to ground. I have not verified here but this is straight from WD.

Janus check PM.

XS Janus · Post by **XS Janus** » Sun May 25, 2008 1:05 pm

Thanks a lot for all your trouble!
I will process all that when I catch some time.

darkmachine · Post by **darkmachine** » Tue May 27, 2008 11:51 pm

Without de-railing the thread, would anyone know why my Adaptec raid won't spin down? No matter what power settings I try in Server 2003, and even when i recreate the entire partition with no files on it (and should therefore be idle), all the drives in the RAID 5 keep humming away indefinately.

Could this be based on the cables as well? I'm just using the native SATAs on my Corsair HX620.