Windows Won't Boot - Too many drives connected to PSU

holygamer

holygamer

holygamer

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Hi, I have the 520W Seasonic Platinum SS-520FL2 Power Supply. Basically Windows isn't booting when I have several drives connected to my power supply.

I have a 6 pin to 4 Sata power cable connected to the PSU. I have 4 8TB hard drives connected to that.

I have another 6 pin to 4 Sata power cable connected to the PSU. I have 3 8TB hard drives connected to that.

I have another 6 pin to 4 Sata power cable connected to the PSU. I have a data SSD drive, SSD C Drive and 2 Bluray Writers connected to that. All those drives are connected to the motherboard NOT the sata card.

I have the following items:
Gigabyte GA-Z77X-UD4H motherboard
8GB Ram
Basic Graphics Card
Intel Core i7 2700K CPU.
8 Port Supermicro SAS/SATA Card. This adds 8 SATA III ports

I used a power reader and all the above is using under 200 watts which is well under the 520W the power supply can manage. So why won't Windows boot when I have all the above drives connected to the power supply?

One of the cables connected to the PSU has a SSD Data drive, SSD C Drive and 2 Bluray writers. If I disconnect all except the C drive, Windows will still NOT boot!
I then unplugged 1 of the 8TB hard drives and it booted. Bizarre.

OR with everything connected, if I disconnect 2 8TB hard drives then it will boot. OR if I disconnect 1 Bluray drive and 1 8TB drive then it will boot. The booting problem happens regardless of whether the CPU is overclocked or not. What's bizarre is that my PC was working fine for days with everything connected. I then needed to restart Windows and it wouldn't boot until I disconnected some drives.

Please help. What am I doing wrong?
 
Last edited:
Hi,

I don't know the ins and outs of this and might be barking up the wrong tree but I'm going to throw this out here, in case it leads to the answer/a solution.

Modern hard drives (from what I've read) use the 5v rail on a PSU. Each rail can only output so much power. In that Seasonic Platinum 520W, the 5v rail outputs 20 Amps (100W). The "520W" part of the name relates to the 12v output, which is normal (except for those cheap PSUs out there that add the outputs of 3.3v, 5v and 12v as part of the PSU name).

So a good PSU will typically have as much output on the 12v rail as it states as part of the PSU name, and then further 3.3v and 5v output on top of that.

Is it possible that all the components using the 5v rail in your system are coming close to max output on the 5v (i.e. 20A x 5v = 100W), and that sometimes it scrapes the limit and fails? Or would they be nowhere close to using 100W? I don't really have a good idea of drive power consumption, just had the impression they use very little. Also, have to factor in that the stated output on the 5v rail in reality may not be completely in line with its specification.

I'd be interested to hear on this from anybody who knows more about this.

And, if that might be the problem, then as a possible solution - would using molex-to-Sata adapters force the PSU to use the 12v rail instead, or would it make no difference?
 
As well as any rail limitations - not sure how PSUs deal with initial in-rush current draw as stuff powers up - you might be within rail specs for normal use but spiking outside of what the PSU can handle on a rail on initial power on.
 
Are you certain that your EFI/bios boot order is remaining consistent? Check disk management when you are in windows to see which disk is marked as boot. (in past experience, it can actually be different to the disk windows is installed to) You then need to set that disk as boot in the bios too. I'll admit that I can't see why it should work fine with all disks and then not all of it's own accord. It's highly unlikely to be a psu issue as hard disks use ~10W during seeking, the biggest drain on power is at spin up.
 
Yes the C drive is set as the boot drive. Each 8TB drive only uses 7 watts. Total of 28 watts per socket plugged into PSU.

I've got 2 LG BH10LS38.AUAR Bluray writers and 2 SSDs connected to one socket of the PSU. I don't know how many watts the writers use as it doesn't say in the manual. SSDs only use 2 watts each.

Don't know what you mean by rails? You said the 5v rail outputs 100w max. All my drives are connected to the peripheral sockets. Are all those sockets combined one rail? Or is each socket a rail?
 
holygamer said:
Don't know what you mean by rails? You said the 5v rail outputs 100w max.
Click to expand...

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http://electronics.stackexchange.com/questions/139481/atx-power-supply-5v-rail-peak-current


holygamer said:
All my drives are connected to the peripheral sockets. Are all those sockets combined one rail? Or is each socket a rail?
Click to expand...

Good question. Actually not too sure how that works, or if it differs from PSU to PSU. I know that some have two or more 12v rails instead of one, and that for some of those - depending on which socket you use, you'll use one or another 12v rail. But mostly they (12v) can pull from all rails if needed, regardless of socket. When it comes to 5v I just don't know. Sorry can't be more help, am interested in knowing the answer myself.
 
You're using the 8 TB Seagate HDDs, right? According to Seagate's website, they use 7.5W apiece. You have 7 of them so they use 52.5W. LG's manual doesn't give the power usage of the BD drives, so I'll assume a similar power usage. The SDD should each use about half. So you're using ~75W on storage.

It may be a BIOS setting, a setting on the controller card, or even a jumper on the HDD, but you can often stagger the power-up times of the HDDs.
 
Could experiment perhaps. Few quid to try out this adapter on four of your drives (connected to the PSU's peripheral 4-pin cable), and see if there's any difference.

YOUR BASKET
1 x BitFenix Molex to 4x SATA Adapter 20 cm - sleeved black/blue/black £5.99
Total : £5.99 (includes shipping : Ex.VAT).



Unless I'm mistaken, a 12v molex will just pull from the 12v rail, whereas the newer SATA can more "intelligently" pull from 3.3v, 5v and 12v as required (which may be a problem in this case). Please correct if wrong.
 
When a HDD starts, there is a larger than rated current draw for a small period of time as the drive spins up.

The SuperMicro card may allow you to enable "staggered spinup" or "power up in standby (PUIS)", which may solve your issue.

Be aware that certain drives don't really like PUIS, and will never be able to spin up without being told to if you move the drives to a raid controller that doesn't support the feature. I had this with a load of WD drives once and was forced to send them all back for warranty replacement.

You could test this by booting to BIOS with only some HDDs powered (data cables connected) then connecting more a batch at a time until all are connected (effectively staggering spin up) then exiting without saving (rebooting without cutting power to drives) to see if everything works.
 
' Each 8TB drive only uses 7 watts. Total of 28 watts per socket plugged into PSU.'
the initial startup load may be a lot higher ie x3 .
try powering the 8tbs from another psu
 
Turns out I need to change "Hard Drive BBS Priorities" motherboard setting to have C Drive 1st. Now Windows boots with 7 8TB hard drives, 2 SSDs and 2 Bluray drives!

What exactly does BBS mean? I never even thought to change that setting since boot order already had C drive first then the Bluray drives.
 
holygamer said:
Turns out I need to change "Hard Drive BBS Priorities" motherboard setting to have C Drive 1st. Now Windows boots with 7 8TB hard drives, 2 SSDs and 2 Bluray drives!

What exactly does BBS mean? I never even thought to change that setting since boot order already had C drive first then the Bluray drives.
Click to expand...

BBS mean BIOS Boot Specification

https://en.wikipedia.org/wiki/Option_ROM#BBS
 
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