What you never knew you didn't know
While researching a few upcoming SD / microSD product reviews here at PC Perspective, I quickly found myself swimming in a sea of ratings and specifications. This write up was initially meant to explain and clarify these items, but it quickly grew into a reference too large to include in every SD card article, so I have spun it off here as a standalone reference. We hope it is as useful to you as it will be to our upcoming SD card reviews.
SD card speed ratings are a bit of a mess, so I'm going to do my best to clear things up here. I'll start with classes and grades. These are specs that define the *minimum* speed a given SD card should meet when reading or writing (both directions are used for the test). As with all flash devices, the write speed tends to be the more limiting factor. Without getting into gory detail, the tests used assume mostly sequential large writes and random reads occurring at no smaller than the minimum memory unit of the card (typically 512KB). The tests match the typical use case of an SD card, which is typically writing larger files (or sequential video streams), with minimal small writes (file table updates, etc).
In the above chart, we see speed 'Class' 2, 4, 6, and 10. The SD card spec calls out very specific requirements for these specs, but the gist of it is that an unfragmented SD card will be able to write at a minimum MB/s corresponding to its rated class (e.g. Class 6 = 6 MB/s minimum transfer speed). The workload specified is meant to represent a typical media device writing to an SD card, with buffering to account for slower FAT table updates (small writes). With higher bus speed modes (more on that later), we also get higher classes. Older cards that are not rated under this spec are referred to as 'Class 0'.
As we move higher than Class 10, we get to U1 and U3, which are referred to as UHS Speed Grades (contrary to the above table which states 'Class') in the SD card specification. The changeover from Class to Grade has something to do with speed modes, which also relates with the standard capacity of the card being used:
U1 and U3 correspond to 10 and 30 MB/s minimums, but the test conditions are slightly different for these specs (so Class 10 is not *exactly* the same as a U1 rating, even though they both equate to 10 MB/sec). Cards not performing to U1 are classified as 'Speed Grade 0'. One final note here is that a U rating also implies a UHS speed mode (see the next section).
Subject: Storage | October 6, 2015 - 07:22 PM | Jeremy Hellstrom
Tagged: Phison PS3110-S10, centon, C-380
The last time we heard from Centon they were using the SandForce 2281 SSD controller, which they have dropped in preference to a Phison controller in their new C-380 series of SSDs. Benchmark Reviews recently reviewed their 480GB model, using MLC NAND and sporting a 4Gb cache of DDR3-1600. The benchmark results were quite varied, sometimes the drive came in at the top of the pack yet other times it was well below average, especially writing to the drive. There is a 1 year warranty on the drive and currently it is on sale at $219 for the 480GB model, down from the list price of $399.99 ... perhaps not a drive to recommend to your friends.
"Centon isn’t a name many enthusiasts will know. I’d never heard of the company myself until this review sample; apparently, they’ve been in business for over 35 years manufacturing DRAM and flash memory products, and have only recently entered the consumer marketplace. The Centon C-380 480GB SSD SATA-III Solid State Drive, part of the “Enthusiast Solutions” series, is the focus of what Benchmark Reviews will be putting through our test suite."
Here are some more Storage reviews from around the web:
- KingFast 256GB F9 SSD Review @ Madshrimps
- Micron M510DC 480GB SSD Review @ NikKTech
- Plextor M6V 256GB @ Kitguru
- The Ultimate Guide To SSD Benchmark Software @ The SSD Review
Subject: Storage | October 1, 2015 - 05:42 PM | Allyn Malventano
Tagged: Samsung, firmware, 840 evo, msata
It took them a while to get it right, but Samsung did manage to fix their read degradation issue in many of their TLC equipped 840 Series SSDs. I say many because there were some models left out when firmware EXT0DB6Q was rolled out via Magician 4.6. The big exception was the mSATA variant of the 840 EVO, which was essentially the same SSD just in a more compact form. This omission was rather confusing as the previous update was applicable to both the 2.5" and mSATA form factors simultaneously.
The Magician 4.7 release notes included a bullet for Advanced Performance Optimization support on the 840 EVO mSATA model, but it took Samsung some time to push out the firmware update that enabled this possibility. We know from our previous testing that the Advanced Performance Optimization feature was included with other changes that enabled reads from 'stale' data at full speeds, compensating for the natural voltage drift of flash cell voltages representing the stored data.
Now that the firmware has been made available (it came out early this week but was initially throttled), I was able to apply it to our 840 EVO 1TB mSATA sample without issue, and could perform the Advanced Performance Optimization and observe the expected effects, but my sample was recently used for some testing and did not have data old enough to show a solid improvement with the firmware applied *and before* running the Optimization. Luckily, an Overclock.net forum member was able to perform just that test on his 840 EVO 500GB mSATA model:
Kudos to that member for being keen enough to re-run his test just after the update.
It looks like the only consumer 840 TLC model left to fix is the original 840 SSD (not 840 EVO, just 840). This was the initial model launched that was pure TLC flash with no SLC TurboWrite cache capability. We hope to see this model patched in the near future. There were also some enterprise units that used the same planar 19nm TLC flash, but I fear Samsung may not be updating those as most workloads seen by those drives would constantly refresh the flash and not give it a chance to become stale and suffer from slowing read speeds. The newer and faster V-NAND equipped models (850 / 950 Series) have never been susceptible to this issue.
Subject: Storage | September 29, 2015 - 07:07 PM | Jeremy Hellstrom
Tagged: tlc, ssd, Samsung 850 EVO 2 TB, 850 EVO, 2TB
That's right, currently $713 will pick you up a 2TB Samsung 850 EVO SSD but how does it perform? The Tech Report is on the case with their latest review, checking out how 32-layer 128Gbit 3D V-NAND with 2GB of DRAM cache and an upgraded Samsung MHX controller perform. It took some doing but once they had filled its over-provisioned area the drive levelled out at 7252 IOps on the random write test though the peak of 84423 was certainly impressive. Check out the full review to see if this is the large sized SSD for you or if you prefer smaller, more agile SSDs which do not use TLC NAND.
If you are like me and running out of mental storage space, you may have already forgotten about Al's review of this drive.
"Samsung now offers its popular and affordable 850 EVO SSD in an enormous 2TB configuration. We put the EVO to the test to see how this behemoth performs"
Here are some more Storage reviews from around the web:
- Plextor M6V SSD @ The SSD Review
- Kingston SSDnow KC380 @ eTeknix
- AData XPG SX930 240GB SSD Review @ Hardware Canucks
- Synology DS215+ 2-bay NAS @ techPowerUp
- Samsung Portable SSD T1 @ Bjorn3d
Subject: Storage | September 23, 2015 - 02:28 PM | Jeremy Hellstrom
Tagged: kingston, HyperX Fury, Ultra II, sandisk, SandForce SF-2281, Marvell 88SS9189
The Kingston HyperX Fury 240GB SSD is currently $90 and the same size SanDisk Ultra II is $86 though the 960GB model that The Tech Report actually reviewed is a relatively decent $300. At those prices they can be quite attractive although there is a big difference between the two drives, Kingston's uses SandForce's SF-2281 while SanDisk opted for the Marvell 88SS9189 controller. Once the benchmarks started the difference did not show in real world applications, both are good performers overall though the HyperX did show some delays in the IOMeter testing. The OCZ Arc 100 that they included did end up on top overall, a strong showing for a drive that is getting a little long in the tooth.
"Kingston's HyperX Fury 240GB SSD and Sandisk's Ultra II 960GB drive both offer solid-state storage at budget-friendly prices for their capacity. We put them through their paces to see whether they're worthy of builders' hard-earned cash."
Here are some more Storage reviews from around the web:
- Intel SSD DC P3608 @ The SSD Review
- The Compact NAS Battle: Synology DS414slim vs. QNAP TS-453mini @ Legion Hardware
- Seagate NAS Pro 6-Bay 24TB NAS Server Review @ NikKTech
- PowerNAS CMA 8TB @ Kitguru
- Synology DiskStation DS715 @ Kitguru
- Kingston DataTraveler microDUO 3C USB 3.1 Drive @ Modders-Inc
- Kingston 32GB Data Traveler Micro Duo 3C Review @ OCC
Introduction, Specifications and Packaging
What's better than an 18-channel NVMe PCIe Datacenter SSD controller in a Half Height Half Length (HHHL) package? *TWO* 18-channel NVMe PCIe Datacenter controllers in a HHHL package! I'm sure words to this effect were uttered in an Intel meeting room some time in the past, because such a device now exists, and is called the SSD DC P3608:
The P3608 is essentially a pair of P3600's glued together on a single PCB, much like how some graphics cards merge a pair of GPUs to act with the performance of a pair of cards combined into a single one:
What is immediately impressive here is that Intel has done this same trick within 1/4 of the space (HHHL compared to a typical graphics card). We can only imagine the potential of a pair of P3600 SSDs, so lets get right into the specs, disassembly, and testing!
Subject: Storage | September 22, 2015 - 06:10 PM | Allyn Malventano
Tagged: vnand, V-NAND, Samsumg, 4TB, 48-layer, 2TB, 1TB
During yesterday's SSD Summit, obscured by their 950 PRO launch was new branding for their 32 (and now 48) layer Vertical NAND technology:
This new branding is more in line with what folks were calling their NAND anyway (Samsung was previously using the term '3D VNAND'. Dropping the 3D made sense, as it was implied with the 'V').
Also of interest were some announcements of upcoming higher capacities of their existing models:
4TB 850 EVO and PRO? Yes please.
1TB in the 850 EVO M.2 edition, and while there is no slide for this, the 950 PRO is also expected to be updated with a 1TB model within the same time frame as well.
How is all of this expansion possible? The answer is their third generation V-NAND, which is 48 layers and 256 GBit (32 GB) capacity per die. Samsung intends to roll this flash out and update all model lines currently using V-NAND technology. This decision was made by Samsung's Senior VP of Marketing, UnSoo Kim:
...now before you get out the pitchforks and form up the 'don't change the flash without a new model' lynch mob, I'd like to point out a few things that make this change different than what you might have seen in the past.
- Samsung is trying to prevent confusion by adding product lines with nearly identical specs.
- Samsung is being very open about this change (others were secretive / deceptive).
- Samsung has promised that they will only implement this change in a way that *increases* the performance and *decreases* the power consumption of these products.
I did leave the Q+A with some further questions about this change. The lower capacities of the 850 EVO still see slower write performance when writing straight to TLC flash (SLC cache is full). This is because there are fewer dies available to write the data, and each die can only write so fast in TLC mode. Since the 48-layer V-NAND is to have double the capacity per die, that would mean half the dies per SSD and possibly slower write speeds in the overall product.
I approached UnSoo Kim after the Q+A and asked this specific question, and his answer was both interesting and refreshing. First, he understood my question immediately and assured me that they will not roll out 256Gbit 48-layer V-NAND into their smaller capacity models - in order to prevent any performance reduction over their current 32-layer equipped parts. Second, he told me that they also intend to produce a 128Gbit variant of 48-layer V-NAND at some point in the future, and use *that* part to substitute the 128Gbit 32-layer V-NAND in those smaller capacity models, keeping the die counts (and therefore sequential write speeds) equal. That additional variant of their third generation V-NAND is the only way (in my mind) that they could update their smaller capacity parts without losing performance, and it was great to see that Samsung has thought out the execution of this rollout in such a proper manner.
Subject: Storage | September 22, 2015 - 02:39 AM | Allyn Malventano
Tagged: vnand, V-NAND, ssd, Samsung, pcie, NVMe, M.2 2280, M.2, 950 PRO, 512GB, 256GB
Samsung’s new product launching will be called the 950 PRO. This will be an M.2 2280 form factor product running at PCIe 3.0 x4. Equipped with Samsung’s 32-layer V-NAND and using the NVMe protocol enabled by a new UBX controller, the 950 PRO will be capable of up to an impressive 300,000 random read IOPS. Random writes come in at 110,000 IOPS and sequential throughputs are expected to be 2.5 GB/sec reads and 1.5 GB/sec for writes. Available capacities will be 256GB and 512GB.
- 256GB - $199.99 ($0.78/GB)
- 512GB - $349.99 ($0.68/GB)
- 1TB - (early next year with the switch to 48-layer V-NAND)
The 950 PRO will be shipping with a 5-year warranty rated at 200 terabytes written for the 256GB model and 400 TBW for the 512GB. That works out to just over 100GB per day for both capacities.
These hit retail in October and we currently have samples in hand for testing.
(for those curious, both capacities only have components on the front side of the PCB)
Subject: Storage | September 21, 2015 - 11:32 AM | Allyn Malventano
Tagged: vnand, Summit, ssd, Seoul, Samsung, M.2, Korea, Global, 2015
As I hinted during last week's podcast, I am in Seoul, Korea to cover an upcoming press conference.
..and with a Samsung SSD Global Summit comes product announcements. Those don't happen until tomorrow (late tonight for you folks back in the states), but I did notice a clue on the cover of our itinerary folder:
See it? Here, let me help:
A VNAND powered M.2 (presumably NVMe) SSD is *exactly* the thing I have been waiting for Samsung to unleash into the wild ever since we reviewed their NVMe SM951. Given that Samsung's prior M.2 offerings gave the Intel SSD 750 a run for its money all while consuming half the power, and did so with Samsung's older 2D Planar NAND, you can bet a VNAND version will be something to behold. Let's hope this new model is released as a consumer product and doesn't end up as OEM-channel unobtanium like the NVMe SM951 was!
Keep an eye out for additional posts from our coverage of the 2015 Samsung SSD Global Summit!
Subject: Storage | September 10, 2015 - 03:30 PM | Jeremy Hellstrom
Tagged: usb 3.1, asus, BOT, UASP
[H]ard|OCP is taking a look at the new USB standard and how it functions on versions of Windows newer than Win7 which support the new transfer protocol. Gone are Bulk Only Transfers, modern OSes support USB Attached SCSI which offers much better transfer speeds. With a Rampage V Extreme USB 3.1 and a bundled PCIe 2.0 x2 USB 3.1 card (available with two USB 3.1 Type A or one of the new USB 3.1 Type C) they tested the difference in transfer speeds between BOT and UASP. Check out their results here.
"Recent changes to the USB spec claim to provide a brighter future for those dependent on USB storage. We have all heard about just how great USB has become, or should have become. We test some of these advances to see if the new USB can deliver the goods when it comes to moving data."
Here are some more Storage reviews from around the web:
- WD My Passport Ultra 2TB Portable 2.5-Inch Hard Drive Review @ Techgage
- Seagate Backup Plus Portable Drive 2TB USB 3.0 @ eTeknix
- SilverStone Teratrend TS432U 4 Bay 3.5" HDD Tower Enclosure Review @ NikKTech
- Synology DiskStation DS415play 4-bay NAS Review @ Techgage
- QNAP TVS-471-4G High Performance NAS with Intel Processor @ Bjorn3d
- QNAP TS-563 @ Legion Hardware
- PowerNAS Business Mini @ Kitguru
- VisionTek Go Drive SSD RAID 0 @ Bjorn3d
- OCZ Trion 100 480GB SSD Review @ NikKTech
- Intel SSD 750 Series Review @ Hardware Secrets
- Crucial BX100 250GB SSD Review @ Madshrimps
- ADATA Premier SP550 @ Benchmark Reviews
- Adata Premier SP550 @ The SSD Review
- Samsung SM863 & PM863 @ The SSD Review