fzabkar wrote:
Roman_TS wrote:
I spoke with our ACE Lab developers and did you know what we found? Everything is very simple - NAND memory in Samsung 840 EVO is TLC based, and it is VERY VERY Bad. After some time when you write the data on memory, the charge inside NAND cells is flow away. The voltage inside cells become worse and worse, and finally - flow away forever. It means that if you will not use your 840 EVO drive for some time, you will find that your SSD is EMPTY.
You ask me - are the guyes from Samsung stupid bastards? Why they did not find the way to fix this bug?!
And I will answer - they release new FW, which make very simple thing - in background, when you working with your laptop or with PC, it just rewrite customer data again and again, again and gain by cycle, every time with the only goal - to keep the data and charges inside cells "fresh". When drive is not connected to power source, charge from cells is flowing away.
Of course this bug fix is not solve the main problem - bad quality of NAND memory.
Wow! Can Samsung expect a class action?
I expect not, as I believe this is deduced not from testing, but using generally accepted "reasons" for why an SSD has failed. such as it has TLC so... it must be that that failed. I would be interested to see the testing report that showed NAND cell voltage flowed away.
They make MILLIONS of SSDs.... so why are we seeing only 10's to Hundreds fail worldwide? That's a pretty good % in my opinion.
In many cases the cause of SSD failure is not found, but guessed at. Actually yet to see a case study that proves a cause of a failure.
Who knows, it may be true.. what I am saying is there is as yet no proof on causes of failure in 99% of cases.