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Community Manager

520 SSD running to spec?

I have a 520 120gb SSD and it seems to run fine.

However, I was wondering about the write speeds

which do not show anywhere near spec. Maybe I have

a mis-marked SSD? Any input will be appreciated.

I paid allot of money for this.

I compared it to a 840 Pro 256 in the same SATA 3

Win 7 HP DV6 notebook with a 2630qm i7 processor.

I used the same program. I cloned the 840 Pro from the Intel.

Superfetch is off as well as indexing and defrag, etc.

I realize the larger capacity drive would perform better

but the write specs of the 520 are not even close

to advertised. I expected this drive to be competitive.

Any consideration would be appreciated.


Here are the numbers from the 520 using

CrystalDiskMark 3.0.1 x 64 :

Read Write

Seq 466.2 150.8

512K 405.3 162.8

4K 23.22 48.29

4K 140.0 150.0


Here are the numbers from the Samsung 840 Pro :

Read Write

Seq 510.3 492.9

512K 443.1 463.9

4K 26.85 51.60

4K 264.3 223.1


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3 Replies
Community Manager

On this case if you want to make sure that the Solid State Drive is working properly I suggest you to install the Intel(R) Solid State Drive toolbox and perform a full diagnostic from the following link:

if you do not get any error message then try a different SATA port, update the BIOS and install the latest SATA drivers available for your system.

Here are the specifications for that Intel(R) Solid State Drive so you can confirm the speed and features of that Solid State Drive:

New Contributor II

CrystalDiskMark uses incompressible test data as default. Drives with Sandforce controllers will only reach their advertised maximum write speed if you feed them compressible data (which you can configure CrystalDiskMark to use).

The more modern controller design of the 840 pro does not rely on compression to reach its write speeds. But you wouldn't see those numbers with a 128GB 840 pro, although it would still be significantly faster than the 520 120GB.

Community Manager

I have updated drivers, Bios etc and run the toolbox once in a while.Thanks for the reply MBV2000.

The machine runs well with the 520 for everyday use but I move large blocks of data occasionally and it could be my imagination but it seems the 840 does it faster which is important to me.

Oken thanks for the explanation about compressible data etc.