Samsung addresses slow 840 EVO SSD performance with another patch

Scorpus

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The Samsung 840 EVO has been one of the most troubled solid state drives since its mid 2013 launch. Last year, users discovered that the drive suffers from performance degredation in the long run, with read speeds dropping off dramatically when old data is being accessed. Samsung issued a patch in October that promised to address the issue, but the fix was only temporary.

Samsung has now released a new firmware patch for the 840 EVO that is said to permanently fix the performance of the drive, as promised. This new patch periodically refreshes the data on the drive by re-writing the contents of an old cell to a fresh one, preventing a performance drop off for old data.

The fix is more of a workaround than a true solution to the problem with Samsung's 19nm TLC NAND used in the 840 EVO. As the drive has to re-write data to new cells every so often, the lifespan of the drive will be reduced slightly, though we don't imagine this will be a significant issue for most users.

If you own an 840 EVO and want to apply the fix to your drive, you can download the latest version of Samsung's Magician tool over on their website. Hopefully this will be the last patch that's needed to fix the performance issue, but it will take a few months to find out if it has worked as intended.

Luckily, the 840 EVO is the last Samsung drive to use 19nm TLC NAND, with newer drives like the 850 EVO opting for Samsung's newer 40nm TLC V-NAND technology which doesn't suffer from the same issue.

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I have bought several 840 drives myself, and our newest machines at work have 120GB 840 Evos. After installing Magician 4.6, I was presented with the option to upgrade to the EXT0DB6Q firmware. I then disabled rapid mode, and ran the benchmark testing(with rapid mode enabled, you're basically measuring your RAM). I saw about a 200 MB/s increase compared to my lowest score for Sequential Write, and more modest gains elsewhere. Note that with Magician 4.6, Standard performance optimization is not supported on Windows 8 or higher. However, a new "advanced" option is available, that performs a complete rewrite, refreshing data and alleviating access delays. It took about 10 minutes to complete on my system with about 60 GB used. I'll be doing more testing, and anxiously awaiting a Mac compatible ISO, as Magician is not available for OS X.
 
Seems the ssd support page now has the .ISO for both OS X and Windows.
 
It seems that TLC NAND isn’t the only type of NAND that's having a problem at process nodes or 19nm of less. The Crucial MX200 SSD which uses 16nm MLC 128Gb NAND flash chips appears to be having the same very issue that the Samsung 840 EVO had, namely NAND flash voltage drifting which causes read speed performance issues on older data.

What does this mean? Well, it means that pretty much NAND flash memory becomes unreliable as the process node shrinks past 20nm. NAND flash manufacturers have hit the wall when it comes to planar NAND. From this point on the only way to make NAND flash reliable is to reverse the process node shrinkage and go to 3D-NAND where NAND cells are stacked on one another instead of laid out flat.

Samsung started this trend in which they released their 3D-VNAND and reversed the process shrinkage to 40nm with their 850 line of SSDs. Other manufacturers are also doing the same with their own approach to 3D-NAND. Ultimately it comes down to the fact that NAND flash memory manufacturers have hit the wall in terms of shrinking NAND and that as you shrink the process node the NAND has far more of a chance of voltage drifting that can effect read speed performance as the data ages.
 
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I have bought several 840 drives myself, and our newest machines at work have 120GB 840 Evos. After installing Magician 4.6, I was presented with the option to upgrade to the EXT0DB6Q firmware. I then disabled rapid mode, and ran the benchmark testing(with rapid mode enabled, you're basically measuring your RAM). I saw about a 200 MB/s increase compared to my lowest score for Sequential Write, and more modest gains elsewhere. Note that with Magician 4.6, Standard performance optimization is not supported on Windows 8 or higher. However, a new "advanced" option is available, that performs a complete rewrite, refreshing data and alleviating access delays. It took about 10 minutes to complete on my system with about 60 GB used. I'll be doing more testing, and anxiously awaiting a Mac compatible ISO, as Magician is not available for OS X.

That "advanced" mode must only show up if you have an 840 EVO installed.
I have an 840 Pro and 850 EVO and there's no advanced option showing up.
What did disappear is the Trim optimization because 4.6 detects Win 8.1.
That sucks because some of my drives are on SATA ports that don't pass through Win Trim commands.
Going back to 4.5 until Samsung rethinks their strategy...
 
So basically what we're seeing is a move like Intel made, when they brought out Tri-Gate transistors.
 
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