Samsung Germany acknowledges '840 Basic' performance slow down, promises fix

Subject: Storage | October 29, 2014 - 03:10 PM |
Tagged: tlc, Samsung, firmware, 840

If you own a Samsung 840 SSD, it appears that after much repeated and vocal pressure, Samsung has acknowledged the slow down also affects your drive. We're not talking about the EVO or the Pro, this is the original pure TLC model that launched (the EVO is a TLC+SLC cache hybrid while the Pro is all MLC). Here's the quote from Samsung, via Computer Base:

Uns ist durch das Feedback, das uns erreicht hat, bekannt, dass es auch beim Zugriff auf bestimmte Daten bei Modellen der SSD 840 zu niedrigeren Leseleistungen als angegeben kommen kann.

Im Moment untersuchen unsere Produktexperten systematisch die betreffenden SSD-Modelle innerhalb verschiedener Systemumgebungen und arbeiten an einer schnellstmöglichen Lösung.

Aufgrund der unterschiedlichen Technologien sind die Modelle der PRO-Serie (840 PRO und 850 PRO) nicht betroffen.

Samsung

What? You can't read German? Neither can we, but paraphrasing from the poor quality translation from several online tools, we deduce that Samsung has acknowledged the issue on the 840, and is working on a solution as quickly as possible. This is similar verbiage to the statement issued for the 840 EVO acknowledgement.

** Update **

Thanks to Zyhmet, who commented shortly after posting, here's a human translation:

Because of the feedback we got, we realized that, accessing specific data with units of SSD 840 could lead to lower reading performance.

For the moment our experts are systematically examining the SSD-units with different system environments and we are working on a solution as fast as possible.

Due to different technologies the PRO-series (840 PRO and 850 PRO) are not affected.

Samsung

** End update **

Side note - of those who have used the 840 EVO Performance Restoration Tool, a few have reported an issue cropping up. The error manifests as a SMART data misreporting error:

temp (cooling).png

What's odd about this error is that it was present on some of our pre-production test samples (firmware EXT0AB0Q), and was corrected once we updated those samples to the first retail build (EXT0BB0Q). The image above was an actual screen shot taken during our temperature-dependency testing of the slow down issue. While none of our samples had the issue return when updating all the way to the performance restored firmware, one of those updates did corrupt the Master File Table, rendering the majority of the SSD inaccessible. While we have seen no other reports of corrupted partitions, several users noticed the SMART reporting issue after updating. It's odd to see this sort of a regression with firmware updates, in that a bug fixed in the initial shipping firmware has returned (for some) in a subsequent update. If you've updated your 840 EVO with their Performance Restoration Tool, it may be a good time to check your SMART attributes. If you see the error above, please leave us a note in the comments.

Circling back to the slow down issue - given that it is present in two TLC-based SSDs from Samsung, one has to wonder if this issue exists in other Samsung TLC SSDs as well. Here's the list of potentials (thanks to an anonymous comment on a prior story):

  • 840 EVO - 19nm TLC
  • 840 - 21nm TLC
  • PM841 - 21nm TLC
  • PM851 - 21nm TLC (some SKUs)
  • 845DC EVO - 19nm TLC
  • PM843 - 21nm TLC
  • PM853T - 21nm TLC

We have several questions out to Samsung on these issues, but to date they have not been answered. More to follow as we wait for an official (English) response.

Podcast #320 - Micron M600 SSD, NVIDIA and Adaptive Sync, Windows 10 and more!

Subject: General Tech | October 2, 2014 - 02:05 PM |
Tagged: X99 Classified, X99, video, tlc, tegra k1, ssd, Samsung, podcast, nvidia, micron, M600, iphone 6, g-sync, freesync, evga, broadwell-u, Broadwell, arm, apple, amd, adaptive sync, a8, 840 evo, 840

PC Perspective Podcast #320 - 10/02/2014

Join us this week as we discuss the Micron M600 SSD, NVIDIA and Adaptive Sync, Windows 10 and more!

You can subscribe to us through iTunes and you can still access it directly through the RSS page HERE.

The URL for the podcast is: http://pcper.com/podcast - Share with your friends!

  • iTunes - Subscribe to the podcast directly through the iTunes Store
  • RSS - Subscribe through your regular RSS reader
  • MP3 - Direct download link to the MP3 file

Hosts: Ryan Shrout, Jeremy Hellstrom, Josh Walrath, and Allyn Malventano

Subscribe to the PC Perspective YouTube Channel for more videos, reviews and podcasts!!

Subject: Editorial, Storage
Manufacturer: PC Perspecitve
Tagged: tlc, Samsung, bug, 840 evo, 840

Investigating the issue

** Edit ** (24 Sep)

We have updated this story with temperature effects on the read speed of old data. Additional info on page 3.

** End edit **

** Edit 2 ** (26 Sep)

New quote from Samsung:

"We acknowledge the recent issue associated with the Samsung 840 EVO SSDs and are qualifying a firmware update to address the issue.  While this issue only affects a small subset of all 840 EVO users, we regret any inconvenience experienced by our customers.  A firmware update that resolves the issue will be available on the Samsung SSD website soon.  We appreciate our customer’s support and patience as we work diligently to resolve this issue."

** End edit 2 **

** Edit 3 **

The firmware update and performance restoration tool has been tested. Results are found here.

** End edit 3 **

Over the past week or two, there have been growing rumblings from owners of Samsung 840 and 840 EVO SSDs. A few reports scattered across internet forums gradually snowballed into lengthy threads as more and more people took a longer look at their own TLC-based Samsung SSD's performance. I've spent the past week following these threads, and the past few days evaluating this issue on the 840 and 840 EVO samples we have here at PC Perspective. This post is meant to inform you of our current 'best guess' as to just what is happening with these drives, and just what you should do about it.

The issue at hand is an apparent slow down in the reading of 'stale' data on TLC-based Samsung SSDs. Allow me to demonstrate:

840 EVO 512 test hdtach-2-.png

You might have seen what looks like similar issues before, but after much research and testing, I can say with some confidence that this is a completely different and unique issue. The old X25-M bug was the result of random writes to the drive over time, but the above result is from a drive that only ever saw a single large file write to a clean drive. The above drive was the very same 500GB 840 EVO sample used in our prior review. It did just fine in that review, and at afterwards I needed a quick temporary place to put a HDD image file and just happened to grab that EVO. The file was written to the drive in December of 2013, and if it wasn't already apparent from the above HDTach pass, it was 442GB in size. This brings on some questions:

  • If random writes (i.e. flash fragmentation) are not causing the slow down, then what is?
  • How long does it take for this slow down to manifest after a file is written?

Read on for the full scoop!

Podcast #312 - Thecus N2560 NAS, ASUS STRIX GTX 780, Flash Media Summit News and more

Subject: General Tech | August 7, 2014 - 01:37 PM |
Tagged: podcast, video, Thecus, n2560, asus, strix, strix 780, flash media summit, Samsung, tlc, vnand, Marvell, gtx 880, x99s sli plus

PC Perspective Podcast #312 - 08/07/2014

Join us this week as we discuss the Thecus N2560 NAS, ASUS STRIX GTX 780, Flash Media Summit News and more!

You can subscribe to us through iTunes and you can still access it directly through the RSS page HERE.

The URL for the podcast is: http://pcper.com/podcast - Share with your friends!

  • iTunes - Subscribe to the podcast directly through the iTunes Store
  • RSS - Subscribe through your regular RSS reader
  • MP3 - Direct download link to the MP3 file

Hosts: Jeremy Hellstrom, Josh Walrath, Scott Michaud, and Morry Tietelman

Program length: 1:00:33
 

Subscribe to the PC Perspective YouTube Channel for more videos, reviews and podcasts!!

 

FMS 2014: Samsung announces 3D TLC VNAND, Storage Intelligence initiative

Subject: Storage, Shows and Expos | August 5, 2014 - 04:19 PM |
Tagged: FMS, vnand, tlc, ssd, Samsung, FMS 2014, Flash Memory Summit

Just minutes ago at the Flash Memory Summit, Samsung announced the production of 32-layer TLC VNAND:

DSC03974.JPG

This is the key to production of a soon-to-be-released 850 EVO, which should bring the excellent performance of the 850 Pro, with the reduced cost benefit we saw with the previous generation 840 EVO. Here's what the progression to 3D VNAND looks like:

progression slide.png

3D TLC VNAND will look identical to the right most image in the above slide, but the difference will be that the charge stored has more variability. Given that Samsung's VNAND tech has more volume to store electrons when compared to competing 2D planar flash technology, it's a safe bet that this new TLC will come with higher endurance ratings than those other technologies. There is much more information on Samsung's VNAND technology on page 1 of our 850 Pro review. Be sure to check that out if you haven't already!

Another announcement made was more of an initiative, but a very interesting one at that. SSDs are generally dumb when it comes to coordinating with the host - in that there is virtually no coordination. An SSD has no idea which pieces of files were meant to be grouped together, etc (top half of this slide):

DSC04016.JPG

Stuff comes into the SSD and it puts it where it can based on its best guess as to how it should optimize those writes. What you'd want to have, ideally, is a more intelligent method of coordination between the host system and the SSD (more like the bottom half of the above slide). Samsung has been dabbling in the possibilities here and has seen some demonstrable gains to be made. In a system where they made the host software aware of the SSD flash space, and vice versa, they were able to significantly reduce write latency during high IOPS activity.

DSC04014.JPG

The key is that if the host / host software has more control over where and how data is stored on the SSD, the end result is a much more optimized write pattern, which ultimately boosts overall throughput and IOPS. We are still in the experimentation stage on Storage Intelligence, with more to follow as standards are developed and the industry pushes forward.

It might be a while before we see Storage Intelligence go mainstream, but I'm definitely eager to see 3D TLC VNAND hit the market, and now we know it's coming! More to follow in the coming days as we continue our live coverage of the Flash Memory Summit!

Computex 2014: Samsung 845DC EVO Enterprise TLC SSDs

Subject: General Tech, Storage | June 4, 2014 - 07:37 PM |
Tagged: computex 2014, computex, tlc, ssd, Samsung, 845DC EVO

Well that was an alphabet soup of a title.

Samsung has just announced a new line of SSDs, based on three bit per cell (TLC) memory, for enterprise customers. The Samsung 845DC EVO is rated at 530MB/s reads with 87,000 IOPS. The company will also cover up to 600TB of writes under its warranty (no mention of length in years, though). The drive will be available "later this month" in 240GB, 480GB, and 960GB models. Samsung did not mention price in their press release, but Anandtech claims the 240GB will be $250, the 480GB will be $490, and the 960GB will be $969.

Samsung's SSDs will give you some TLC???

This is basically $1/GB scaling, plus $10. I must admit, this is getting pricy. In the consumer space, we have recently seen 512GB for $199. That said, SSDs are not known for sticking to their MSRP. Also, these are enterprise-rated drives. Being TLC-based, I wonder how much (if any) SLC-style write cache was included, as per the consumer 840 EVO.

Lastly, Samsung claims that these drives use around 4W under load. This is much lower than hard drives but a little high for SSDs, according to benchmarks that I have seen. That said, there are a few ways to parse that (for example, if they mean that its peak is typically 4W, which would be pretty good for a 960GB drive).

The Samsung 845DC EVO will be available later this month for a little over $1/GB.

Source: Samsung

Using TLC flash to offer consumer level pricing to data centers?

Subject: General Tech | April 30, 2014 - 12:59 PM |
Tagged: Samsung, ssd, tlc

Samsung has been working with TLC flash for a while now, both the original 840 and the 840 EVO utilize that type of flash, the increased yields offer lower pricing at the cost of a reduced number of writes before the flash begins to fail.   The Register has posted their announcement of a new product line aimed at the data centre; the PM835T family will come in 240GB, 480GB and 960GB models and will also use TLC flash, with pricing predicted to be comparable to consumer level drives.  With Samsung's 10nm-class TLC flash the experts at SMART suspect a 500 phase/erase cycle lifetime however depending on how Samsung has designed the drives the actual number could be much higher, they do offer a 3 year warranty on their current TLC drives.  For now Samsung is not releasing an official expected lifetime for these drives which raises a question, will enterprise feel the short term cost savings are worth the long term replacement costs?

samsung_pm835t.jpg

"Triple-level cell (TLC) flash chips mean fabs can extract more flash capacity from a silicon wafer, and so production costs are lower than for two-level cell MLC technology. Samsung says it gets "a 30 per cent increase in manufacturing efficiency compared to SSDs that use 2-bit NAND flash components."

Here is some more Tech News from around the web:

Tech Talk

Source: The Register

More on Samsung's new cached SSD wizardry

Subject: Storage | July 26, 2013 - 06:08 PM |
Tagged: TurboWrite, tlc, ssd, slc, Samsung, 840 evo, MEX controller

Along with Al's review of the new EVO line you can get a second opinion from The Tech Report about the performance of the new SSD with a fast cache.  The majority of the storage is 19nm TLC NAND but there is an SLC cache sitting between the controller and that long term TLC storage to help with the overall responsiveness of the drive, aka TurboWrite. In the 120 and 250GB models that cache is 3GB while in the larger models you get a 6GB cache.  In their real world testing the new EVO drive is incredible at large file copying though Sandforce drives can beat it in small file copy speeds, likely thanks to the compressed write trickery that controller family is so good at.  Check out the review here and keep your fingers crossed that MSRP is the acual price these drives sell at.

TR_nand.jpg

"Samsung's entry-level 840 EVO SSD combines affordable TLC NAND with a server-style SLC cache. We explain the drive's unique buffering tech and explore how it affects performance."

Here are some more Storage reviews from around the web:

Storage

Subject: Storage
Manufacturer: Samsung

Introduction and Specifications

Introduction:

Last week, Samsung flew a select group of press out to Seoul, Korea. The event was the 2013 Samsung Global SSD Summit. Here we saw the launch of a new consumer SSD, the 840 EVO:

IMG_0007.JPG

This new SSD aims to replace the older 840 (non-Pro) model with one that is considerably more competitive. Let's just right into the specs:

Read on for our full review of the 500GB and 1TB models of Samsung's new SSD!

New Samsung 840 EVO employs TLC and pseudo-SLC TurboWrite cache

Subject: Storage | July 18, 2013 - 01:12 AM |
Tagged: tlc, ssd, slc, sata, Samsung, cache, 840 evo

Samsung's release of the 840 EVO earlier today likely prompted some questions, such as what type of flash does it employ and how does it achieve such high write speeds. Here is the short answer, with many slides in-between, starting off with the main differences between the 840 and the 840 EVO:

DSC04627.JPG

So, slightly increased specs to help boost drive performance, and an important tidbit in that the new SSD does in fact keep TLC flash. Now a closer look at the increased write specs:

DSC04633.JPG

Ok, the speeds are much quicker, even though the flash is still TLC and even on a smaller process. How does it pull off this trick? Tech that Samsung calls TurboWrite.

DSC04637.JPG

A segment of the TLC flash is accessed by the controller as if it were SLC flash. This section of flash can be accessed (especially written) much faster. Writes are initially dumped to this area and that data is later moved over to the TLC area. This happenes as it would in a normal write-back cache - either during idle states or once the cache becomes full, which is what would happen during a sustained maximum speed write operation that is larger than the cache capacity. Here is the net effect with the cache in use and also when the cache becomes full:

DSC04638.JPG

For most users, even the smallest cache capacity will be sufficient for the vast majority of typical use. Larger caches appear in larger capacities, further improving performance under periods of large write demand. Here's the full spread of cache sizes per capacity point:

DSC04639.JPG

So there you have it, Samsung's new TurboWrite technology in a nutshell. More to follow (along with a performance review coming in the next few days). Stay tuned!