1 Power Cable for 3 Hard Drives

[andreoei]

Hi everyone,

First time poster here.

I just installed a new SSD and new HDD so I have 3 hard drives in total.

The guy fixing up my desktop told me that my power unit can power all 3 but I should not rely on just 1 cable running in series. So he asked me to add another cable.

Is this a valid concern or is he fearmongering?

Thanks v much for your advice. Details below.

SSD 500gb
HDD 3TB
HDD 2TB

Cooler master G650M 650W

Andy

 

[AniChatt]

It will not be any issue. However if you are so much worried, you can go for two cable one is for SSD and other one is for HDD (two hdd in one cable). However there is less than say 0.001% chance that you may face any problem with hdd/ssd power supply as long as your PSU has enough power to feed other components.
The psu has enough power to support 3 drives at a time and this is the reason why they have provided 3 pin on a single cable. Cooler master is a good brand and they will not make any stupid design. So just trust the brand and if they have provided 3 ports for sata power they must have done some research. just make sure your PSU is good enough to surpass power requirement of our entire system.
Is 650 watt is recommended by any renowned PSU calculator website? if yes then plug it and forget it.

 

[Solandri]

The SSD isn't a problem. The HDDs can be. They only use about 1-7 Watts in regular use. But when they spin up (when you first turn the computer on, or when you wake the drive from sleep), they can draw about 15-45 Watts each (energy needed to get the platters spinning).

http://www.45drives.com/wiki/index.php?title=Start_up_Power_Draw

Multiple HDDs on a single power cable can thus overwhelm the cable's ability to provide enough power. For this reason, motherboards will spin up each HDD with a random delay if you have multiple HDDs, so that their power spike doesn't hit the PSU at the same time. Two HDDs on a single power cable should be fine. Maybe once in a blue moon the computer may fail to start properly or may not detect a HDD, but it's no big deal (unless you've also got a marginal power supply).

A quick search says the SATA spec is a max 4.5 Amps per power rail, so in the case of the 12V rail this is 54 Watts. Plenty for a single HDD to spin up. But it's conceivable that if you have heavy HDDs (lots of platters) and they both try to spin up at the same time, you could exceed 4.5 Amps (54 Watts). The staggered spin-up should prevent that from happening 99.9% of the time though.

 

[andreoei]

thanks very much solandri and anichatt!