Samsung 950 pro m.2 missing 35GB

[k1lly]

Hello guys, please help me getting back missing 35GB of drive capacity.

The drive is Samsung 950 pro M.2 512 GB.

What happened:

1. I've installed Windows 10 x64 on my new machine, everything worked fine, 512.11 GB was available.
2. formatted the whole disk (not a big issue), but I got error message like that: 

Device says hardware cluster size is 2048 Kbyte, but driver says it's 512

1. I went ahead and installed Ubuntu, then figured out something's wrong with the disk capacity.
2. Wiped disk again and reinstalled Windows 10 on another ssd in the machine, and got only 477 of 512 GB available on the M.2 disk.
3. Disk management doesn't show any unallocated space.
4. Samsung Magician shows only 477 of 512 GB available, even after two attempts of factory reset.
5. Tried formatting using HDD Low Level Format Tool - both quick and full with no effect on capacity.
6. Tried manipulating disk using Gparted from live USB and MiniTool Partition Wizard with no results.
7. As I can see, now disk cluster size is 512 Kbyte.

Tried issuing a ticket with Samsung support and called the hotline with no positive results: they told me that it's because the manufacturer calculates capacity using 1000 bytes per Megabyte, not 1024 (guess that indicates level of knowledge and helpfulness).

 

I've attached system report exported from Samsung Magician and screenshot showing available capacity as well.

 

Please help, I'm completely lost!

error950pro.csv

[Sakkura]

Samsung support already gave you the correct answer. 512 GB is the same as 477 GiB. SSDs and HDDs are sold in GB (or TB), but Windows and many programs use the slightly different binary units GiB (and TiB).

[k1lly]

2 minutes ago, Sakkura said:

Samsung support already gave you the correct answer. 512 GB is the same as 477 GiB. SSDs and HDDs are sold in GB (or TB), but Windows and many programs use the slightly different binary units GiB (and TiB).

 

After initial installation of Windows 10 I've got correct capacity of 512.11 GB, not 477.

And Samsung Magician Software indicated 512 GB of storage correctly as well.

[Sakkura]

1 minute ago, k1lly said:

After initial installation of Windows 10 I've got correct capacity of 512.11 GB, not 477.

And Samsung Magician Software indicated 512 GB of storage correctly as well.

Where did you see that "correct" capacity?

[Simon771]

500GB = 465GB

So 512GB seems to be 477GB 

 

It looks fine to me.

[k1lly]

Just now, Sakkura said:

Where did you see that "correct" capacity?

Under disk management, in "my computer", and in Samsung Magician Software (just like on the screenshot in the initial post), but the numbers were correct.

[k1lly]

Maybe, maybe I need to reformat the disk to 2048 Kbyte cluster size.

Can you tell me how to do that and what file system should I choose?

[Sakkura]

1 minute ago, k1lly said:

Under disk management, in "my computer", and in Samsung Magician Software (just like on the screenshot in the initial post), but the numbers were correct.

It's possible they just report the GB capacity instead of converting to GiB, before the drive is partitioned and initialized.

 

In any case, there are no missing GiB, the true usable capacity of the drive is 477 GiB = 512 GB.

[DHelios]

Slightly off-topic perhaps, but I have to say it's simultaneously weird and delightful to see people actually use Gibibytes and Tebibytes...

[WereCat]

I have 850 EVO 500GB and it reports as 465GB so I guess for 512GB the 477GB you see should be correct.

[k1lly]

The exact error message I got while partitioning disk in Ubuntu was:

physical block size is 2048 bytes but linux says it is 512 bytes

 

[Sakkura]

It's using some type of 512-byte emulation. I wouldn't worry about it if performance is alright.

[k1lly]

I knew my eyes weren't deceiving me.

Guys, I've figured this out — my BIOS was totally messed up.

After loading optimised defaults I've got everything back.

When I get Windows 10 back I'll provide screenshot. In the meanwhile enjoy MacOS Sierra stats.

[k1lly]

I'd like to trial you all for correct answers, but I had to be stubborn enough to understand the issue myself. Turns out that Mac OS displays disk "advertised" capacity while windows shows actual one. The drive on the screenshot above is listed as a 931 GB drive in Windows