# Samsung 840 SSD write speed absymally low



## simaomacaco (May 2, 2015)

Hello clever people,

I just bought another SSD (Crucial MX100) and was benching it against my existing Samsung 840 which I use as primary partition.  In doing so I get the following results:

Two disks:
..samsung 840 is 150/250gb full,   ACHI on, condition good, write caching OFF
..crucial mx100 is 100/500gb full

Both are using 

using ATTO:

Samsung 840 results: Awful write speeds 





Curical results: Seems a good job, pretty fast and meets the stated specifications.





Any thoughts on what I can do to determine why the Samsung is performing like an old tart?


----------



## m6tzg6r (May 2, 2015)

840 EVO? Yeah they have an issue with degraded performance. But there is a firmware update to fix it i believe.

I own a 250gb and a 500gb 840 EVO but havnt seen any issues. I did update the firmware last week for the hell of it.


----------



## P4-630 (May 2, 2015)

http://www.samsung.com/global/business/semiconductor/minisite/SSD/us/html/support/downloads.html


----------



## Ruyki (May 2, 2015)

The common 840 EVO performance degradation issue is that read speed of old files is slow. Slow reads of new files and writes are not explained by it. You may have another problem.

Try another cable and port.


----------



## Aquinus (May 2, 2015)

Could we get a screenshot of the SMART attributes for the Samsung drive?


----------



## simaomacaco (May 2, 2015)

Okay, I think this is revealing.

Samsung 840 pro






New Crucial MX100 shows:


----------



## jsfitz54 (May 2, 2015)

SEE:  http://www.techpowerup.com/forums/threads/fyi-samsung-840-evo-fix-in-the-works.211963/

Also, if you cloned from spinning HD, then do a fresh reinstall of OS directly to SSD.

Use current Firmware.

Use Samsung Magician 4.6. "Performance Optimization", "Advanced Tab"


----------



## flappyone (May 24, 2015)

simaomacaco said:


> Okay, I think this is revealing.
> 
> Samsung 840 pro



There are C7 - CRC Error counts. In 99% they are related to a lose or broken SATA cable. If the Cable is broken, the raw value will increase. You should change the cable and check the status again after a short time. Compare it. If the value stays at B5, it is fine. (It will not decrease or reset ever)


----------

