Why can my HDD spin up with 1 W when it should take 5 W?

Years ago, I asked a question in the following thread:
[Does the problem lie in the USB panel?]

Last month, I bought a new USB HDD without external power supply. An online PDF file shows the following power requirement:
Spinup (max) 1.00A
As per the requirement, the new HDD takes 5V x 1A = 5 W to spin up.

I did the following test:
A USB hub was connected only to a USB 2.0 port. A spinning USB fan was connected to the hub. I plugged the new HDD into the hub. The HDD spun up and worked properly.

I believe the USB fan took only 1.5 W although the label said "2.5 W". As a USB 2.0 port provides 2.5 W of power, why could the HDD spin up with only 1 W although it should take 5 W as per the PDF? Nowadays, is it common for a 1-TB USB HDD to be so power-saving?

 

Over the past several years, my old USB HDD did not get enough power from a USB hub. I am interested to know more about power consumption.

 

Says who?

"Max" does NOT mean that is how much it "should" take. That just means it "should" require no more than that.

 

It requires no more than 1.00A. 100mA is no more than 1.00A. Perhaps it requires just 100mA.

 

Motors always (and most electronics, actually) require more energy to start than to keep running. So it might, for example, consume .5A (500mA) when going from off (0RPM) until it reaches full speed at 5400RPM (or 7200RPM or whatever speed it is rated for). Then, like all motors (even car engines), they take less energy to maintain that speed so it then may settle down to 100mA.

And yes, today's hard drives are more efficient than those of the past.

 

The HDD inside the enclosure is just 7 mm thick. In 2016, when it was first released, the manufacturer said that "It is also the fastest and most power efficient 7mm drive in the industry". I wonder whether other manufacturers can produce comparable disks now.

 

Understand that could sure be a bunch of marketing malarkey too.

But no doubt, in the 5+ years since, drive performance has improved and drives have become even more efficient.

 

I replaced where ever possible, any external enclosures with SSD's.
Work faster and very low current draw.

 

Has any one of you ever used a USB HDD as power efficient as the one below?

A USB hub was connected only to a USB 2.0 port. A spinning USB fan was connected to the hub. I plugged the new HDD into the hub. The HDD spun up and worked properly.

I was rather surprised at the power efficiency, as my old USB HDD was power hungry.

I just found this article: Hard disk case: hard disk spin retry errors
It says that "a single USB 1.1/USB 2.0 connector can provide up to 500 mA power which is insufficient for most 2.5" notebook hard disks to spin up and operate properly."

My USB HDD is actually a 2.5" notebook hard disk.

 

Recommendations
I think this advise should be followed, but as I Posted earlier---SSD's are the way to go.

• always use USB connections located on the rear panel of the motherboard when connecting external USB hard disks.
  
  
• connect external hard disk drives to the computer / notebook with double Y USB cable.
  
  
• always connect these 2 USB connections to the computer / notebook first and finally connect the one mini-USB end of the cable to the hard disk.
  
  
• avoid using "front panel" USB connectors and USB extender cables when connecting external hard disks.
  
  
• carefully use USB hubs, try one of them if required
  

 

The quoted recommendations apply to a power-hungry disk like my old USB HDD, which requires a USB hub with external power supply.

 

Do you consider SSDs as reliable as HDDs for backups?

 

Just by the fact that they have no moving parts, SSD's will be less prone to internal damage unlike a HDD which has spinning platters and the larger the capacity of the HDD, the larger the number of platters. Dropping, knocking are the HDD biggest problem.
The SSD is silent in operation, where the HDD can become noisy over time.
Technology moves pretty fast these days and I'm using NVMe SSD cards as they take less space and are generally very fast in both Read and Write speeds.

 

My one-platter USB HDD is so silent that I do not know whether the disk is still spinning or has stopped spinning. No rotational vibration can be felt either.

 

If a USB hard drive, the enclosure is probably helping to suppress noise too. Also, many external USB drives use much slower drives than typically installed in PCs.

Internal PC drives typically spin at 7200RPM. Many at 10,000RPM. Faster speeds tend to produce more noise.

Drives used in laptops and external enclosures typically run at slower speeds primarily because slow speeds require less power. And faster drives run down the battery faster. So it is likely the drive in your USB drive runs at 3600, 3811, 4000, 4400, 4500, 5200 or 5400RPM.

Also, we (humans) typically don't realize how noisy our environment is until all power is lost. Then the silence is deafening.

Okay. But what does that have to do with your question; are "SSDs as reliable as HDDs for backups?"

For long-term (disconnected and unused in storage for many years on the shelf), a hard drive is probably considered more reliable - in terms of data retention. But this is not a good policy, even with hard drives as they can still suffer from "bit rot" but also, mechanical parts, including motors, can seize if left unused for long periods of time. So even with a hard drive, it should be powered up every year or so and the data should be "refreshed". This can be done by using the drive to store a new backup copy of your data, or to use a program like "DiskFresh" that simply reads, then writes back the same data to the disk, thus refreshing the magnetic charge at each location. SpinRite will refresh the data too.

For SSDs, the process is easier. Just connect power for a few minutes. No need to rewrite the data. Nor is there a concern about mechanical parts seizing.

Regardless, any robust backup plan involves multiple backup copies, with at least one stored off-site.