Solid State Drive (SSD) Comparison List

[spookshow]

Introduction
Until a few years ago, it was difficult to investigate a viable technological alternative to the hard drive. Storage device per excellence, and also the drive in 2006 celebrated its half century of existence. In 2009, if the hard disk has become more than ever the storage solution providing the cost per gigabyte, as a result of which, SSD technology overtook and now is growing to the point to justify this comparison.

The DSS for Solid State Drive, refers to compounds disks, not magnetic platters, but flash memory chips. The data is written on flash memory chips which offers two immediate advantages over the hard drive, access time of much lower and, especially, lower power consumption with the promise (not always held) performance higher. Side of the coin, SSD technology is expensive and offers reduced storage space. While the first hard drive came to € 80 offers 1TB of storage, the SSD with 80 GB of storage can be traded 400 euros each!

We will see through this comparison, if the difference in price is justified as we seek to explain the differences in technology, to analyze the performance and trying to sort in which an offer becomes inefficient. All the big names in the memory are in fact being SSD from Corsair to OCZ through Kingston as Samsung and Intel are also developing similar solutions. All are not present in this comparison, the manufacturers will send their products to the press test is quite variable. SanDisk Corsair and thus are absent from this issue ...

SSD technology in detail: the architecture of memory
During our first record on SSD drives, the future of hard disk happen by the DSS? We already have mentioned the advantages of this type of drive face to traditional hard drives. We therefore do not return it, preferring to plunge us further forward in the retail technology. Physical disk SSD is composed of three elements: a PCB, single plate of silicon memory chips soldered on the PCB, and a controller controlling the whole. On memory, SSD drives use memory type NAND flash non-volatile.

There are two types of memory chips with SLC and MLC technologies. The chip type SLC (Single Layer Chip), storing one bit per transistor and are advertised as able to collect a total of 100 000 cycles erase / write. Meanwhile, MLC chip (Multiple Layer Chip) have a shorter life, namely 10 000 cycles erase / write but as they are cheaper and offer a storage capacity doubled in size chip equivalent. In terms of performance, the SLC chips offer theoretically better rates than MLC chips.

In terms of memory chips themselves, each is structured according to relatively complex blocks, themselves divided into pages. For example, a memory chip with a capacity of 2 GB, the blocks are typically 128 KB for page 2 Kb each. Read the operating mode of the memory requires the total load of the page or pages of writing while in each block must be written in its entirety. This means that writing 16 KB of data memory the process will take as much time as he had to write 128 KB ... A real problem in terms of performance.

It is possible to circumvent this limitation by implementing cache or directly at the controller (on die) or through an external chip. With this in mind, some DSSs include a fourth element in their anatomy: a DRAM chip to act as cache. Warning, this is not systematic.

Finally, each SSD, you will have understood, controlled by a controller. It is a type of chip SoC (System on a chip) comprising the interface input / output, a real processor. The controller also provides algorithms that are crucial to the overall performance of the disk. From a manufacturer to another, the controllers used vary and if it plays an important role in the overall performance of the disk, it must of course not lose sight of the memory technology used.

SSD Drives: Importance
With the growing technology, SSD's have taken an important place in today's world as compared to old hard drives. On an SSD, memory chips store data in the form of electrons, but with time, their cells are no longer able to retain power and they become unusable. To prevent wear and tear occurs too quickly, especially in writing on the same cells always, manufacturers have imagined the wear leveling: when writing data, the disk controller ensures and distribute them on up cells. To do this, the controller means to know precisely the number of entries received by each memory block .... With this information, it may allocate the best data.

Meanwhile, in addition to wear leveling, SSD drives incorporate ECC control errors. Specifically, when writing data if the disk controller detects an error, it immediately marks the defective memory and blocks and writes the data to another location on the disc. Naturally, the penalty in performance is not trivial in this case.

Developed in 2007, the TRIM complements the arsenal of ATA commands and is meant to provide a real solution to the problem of performance degradation of DSS for use, a concept that goes hand in hand with wear. his is a command to the operating system to indicate the disk, in this case our SSD, a logic block, or LBA, contains invalid data. In fact that when deleting a file from the operating system, the file is simply deleted the references to the allocation table of the disk: the data file are still present in the blocks and pages of our cell memory chips.

But before you can post again in these pages, it is imperative that they be erased. And not to fix our business, erasure occurs on a large scale: it is not possible to delete individual pages, and it is the entire blocks of 128 KB or more that must be reset . The TRIM will tell the disk controller to reset the cells, while another controller is aware of the physical memory pages available for writing data. At the risk of slowing the process of obliteration, TRIM is supposed to maintain at least constant write performance of DSS.

Remaining as a detail, the TRIM only works if the disk controller SSD supports in conjunction with the operating system. For now, Windows 7 should be capable, in its final version, to take over the controls TRIMs. As for SSD drives, Intel will soon offer a firmware update of its disk to add support for TRIM OCZ already then this function for discs Vertex via a firmware update from them.

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Comparison of SSD Disks: Kingston, Intel, Samsung and Corsair

Kingston SSD M Series - 80 GB
Specialist markets Kingston memory a few months ago launched a range of SSD drives. However, do not think SSD drives from Kingston are developed in-house since it is simply not the case, at least for the series E and Mr. Kingston was pleased indeed to sell the discs produced by Intel SSD without making other changes as affixing a sticker to its colors.

The Kingston Series M SSD drive is a 2.5 inch format offered in capacities of 80 GB or 160 GB model received for this test is a 80 GB disk composed of twenty memory chips type MLC, engraved in 50 nm and interfaced to 10 channels. It manages the interface Serial-ATA 3.0 Gb / s, NCQ, and uses an Intel chip supported by Samsung SDRAM with a capacity of 16 MB On paper, the performances on this disc are announced as follows: a flow rate reading of 250 Mb / s for write speed of 70 MB / s.

Intel SSD / Kingston X25-M 80GB

Note that the disc has recently benefited from an upgrade of its firmware, following the deterioration of its performance in some specific cases. The firmware fixes these problems in 8820 and settled without erasing the data on disk. The drive that we tested is equipped with this firmware. Please note that Intel will offer a few weeks a new firmware adds support for TRIM.

Intel X25-E - 32 GB
Intel in terms of SSD, the X25-E was one of the SSD the most difficult to achieve this comparison. It must be said that its unit price is much higher than that of the X25-M in particular, but that is not the issue. Available in 32 versions and 64 GB, the X25-E is as his peers as 2.5 inches when it uses memory chips type SLC is the only one of our comparative use this type of technology. Chips that are etched into 50 nm. Using technology ten channels of Intel, the DSS has a twenty chips each or 2 GB storage space 40 GB on the 40 GB, 32 GB currently available, the remaining space being allocated to the likely replacement in case of emergency, cells deficient.

About the performances, Intel announced in reading speeds of 250 Mb / s and write speeds of around 170 Mb / s. Using the interface Serial-ATA 3 Gb / s, the disk is supported by 16 MB of cache. The disk controller is on models like Kingston, a smart home, Intel signed and supporting technologies including SMART and NCQ.

Intel SSD X25-E, here in the 32 GB version

Designed by Intel in the business world, the X25-E is distinguished, in addition to performances by its durability. Indeed, the SLC memory cells are supposed to collect a larger number of write cycles than their MLC. Intel insists on various aspects of its X25-E including the wear-leveling. This setting is enhanced by the choice of Intel technology which aims to address the phenomenon of amplification of writing (a term no barbaric related to the ratio between the size of the smallest memory block and the size of the file to write ). Through its proprietary controller, Intel builds on the NCQ but also buffer hard to make the best use of each memory cell, avoiding unnecessary deletions. According to builders and deletions with an average volume of 20 GB per day for five years, the X25-E will run out in 1380 cycles of erasing against 68,000 for a SSD normal. As the X25-M, X25-E will soon benefit from an update to its firmware to support the TRIM.

Samsung SSD PB22J - 256 GB
At Samsung, we could not ignore DSS while the Korean firm is the largest manufacturer of flash memory in the world! Thus, the manufacturer offers several models of SSD in several capacities. We are interested in today PB22J, aka MMD0E56G5MXP, a disc of 256 GB SSD if, like his comrades, an interface-Serial ATA 3 Gb / s. Note that the Samsung models available in 64 and 128 GB

Technically, the Samsung uses disk controller as an ARM processor (controller S3C29RBB01) when it has 32 memory chips of 8GB MLC each chip Samsung signed of course! The controller is supported by 128 MB memory buffer, the DDR-SDRAM. Later specifications, Samsung announced a write speed of 220 Mb / s and a write speed of 200MB / s for the 256 GB model 128 GB model offers the same rates as its variant will have 64 GB of content for a rate announced in writing to 120 Mb / s.

Samsung SSD PB22J - 256 GB

Corsair P128
The Corsair memory manufacturer, has for some years already diversified. Since memory cards and USB keys through the feeds, the manufacturer has also ventured into the field of liquid cooling systems. More recently, Corsair has attacked the SSD market for discs. A strategic choice quite logical for a firm that specializes in flash memory.

Newest in the range of SSD Corsair: the P128, a 2.5 inch disk using Samsung and similar components in the technical PB22J, the SSD drive developed by Samsung. Besides, Corsair offers a full range with the P256 but the P64. Side characteristics, in addition to the use of the Serial-ATA interface and support for NCQ, the P128 is announced for read speeds of around 220 MB / s against 200 MB / s average speeds writing. It is run by a Samsung ARM processor with integrated 128 MB of integrated cache. The chips in charge of data storage are naturally signed Samsung and is MLC memory.

Corsair P128: assumed as a clone of the Samsung!

Note, the feature called Performance Recovery is highlighted by Corsair. It is integrated in the firmware of the disk and is designed to address the same problem as the TRIM command, the physical presence of invalid data in memory blocks same as when they were erased. Operating in a transparent manner, the feature called Performance Recovery starts after an hour of inactivity the hard and can last a maximum of one hour. His goal? Implement various empty memory blocks can be used subsequently for writing to ensure the best possible rates. Warning: this feature is compatible with NTFS.

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Comparison of SSD Disks: OCZ SSD Range

OCZ Solid Series - 120 GB
Having made a name in the segment memory alongside a Corsair yet well established, the manufacturer OCZ has launched soon in the battle of the DSS. So much so that it offers a full range of SSD drives in all prices, or almost. The OCZ Solid Series, tested here in the 120 GB version, is the entry level in terms of SSD at OCZ. The disc in this format 2.5 "and uses the Serial-ATA interface. It has, and is an original, a mini-USB connector to connect to a PC via a cable, not supplied, using the USB interface.

Technically, Series Solid discs use Samsung flash memory (16 chips on the 120 GB model) type while the MLC controller is a circuit JMicron, type JMF602. Problem because there is problem, the JMF602 is sadly known for its poor performance. It must be said that the controller, among other defects, can not handle external cache: it has 16 KB of internal cache memory, and not a byte more! In comparison, the Intel SSD controller board, in addition to the external cache, 256 KB cache on-die. "

MF602 JMicron controller: a controller

Inevitably, when the size of a block is 128 KB, have 16 KB of buffer memory is somewhat under-sized and a misfortune never comes alone, JMF602 is also affected by latency too high. No need to expect high performance of the range of SSD Solid Series OCZ as we see later in the tests. The advertised rates are 155 Mb / s read and 90 MBps write.

OCZ Apex Series - 60 GB
OCZ in the series, I ask the Apex! For the manufacturer of memory, Apex models are the mid-range offering. Also in 2.5 inch format, with a Serial-ATA connectors (exit USB), Apex uses flash memory chips Samsung MLC type. The surprise comes from the controllers because the disc has not one but two controllers JMicron JMF602 here in revision B with premium chip JMB390!

OCZ Apex Series and JMicron controllers

Usefulness of such a process? Offer high performance by operating the memory chips of SSD RAID 0 mode, while the disc is seen as a single physical machine. The theoretical rates are doubled and OCZ Announces Apex for its disk of 60 GB, a reading speed of 230 Mb / s for a write speed of 110MB / s.

OCZ Vertex Series - 120 GB
The high-end OCZ is represented by the series of discs Vertex. The disc model used is a 2.5 inch, Interface Serial-ATA. Classical in appearance, it is distinguished by its controller, a chip Barefoot, supported by 64 MB of cache memory. In its 120 GB, the drive is equipped with 16 memory chips, chips Samsung MLC type.

Returning briefly to the controller Barefoot and signed resulting of a startup founded by former executives of Samsung. The controller is based on an ARM7 processor and can manage an external cache, nothing really new under the sun, therefore, even if Barefoot is used by a growing number of SSD drives. As for the Vertex 120 GB, it was announced by OCZ as offering speeds of 230 MB / s read and 135 MB / s write.

The OCZ Vertex 120 GB

With its upmarket positioning, the Vertex of OCZ advantage of regular updates of its firmware. These aim to optimize the algorithms for optimal performance. Problem: each firmware update, data from the disk are lost! An elegant ... and very little to say the least unique.

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Conclusion
Undoubtedly, the SSD drives are expected to spread in our machines. Their advantages are many, including their small size, their power consumption is very less or the total absence of noise.

Operating systems do not necessarily make the best use of SSD controllers while the employees on low cost models tend to equalize their performance down, making them sometimes slow a traditional hard drive ... if not more!

Gradually, the software evolves, however, take into account the specificity of SSD drives. So, Windows 7 should make some improvements in this direction while the SSD manufacturers are now widespread implementation of TRIM orders, sometimes at the price of a firmware update. Also welcome the efforts of OCZ in this area, the manufacturer providing a sound account of its high-end SSD, the Vertex, which has regular updates. OCZ always with the range of SSD seems solidly designed and regularly promoted and put forward by the brand. For it must be noted that some manufacturers such as Sandisk are strong in ads, but much more discreet when it comes to sending their products to the press for testing. Would they have something to hide?

In any event, one of the DSS that we test we will have several models: OCZ Vertex certainly offers very high performance level that make it an excellent choice as its price, about 380 euros, remains almost reasonable DSS at this level. Of course, the famous-E X25 Intel makes it wrong sometimes but at about 400 € for 32 GB, the performance will pay dearly loved!

At Samsung, the PB22J with 256 GB of space is a very good choice, however, back on certain areas, whereas level pricing, storage space on our test sample, 256 GB, resulting in a price around 700 euros. Price for the crippling less! Indeed, the P128 of Corsair could hold its own: while it has two times less disk space but the cost is accordingly lower. And of course there is the X25-M result of the union between Intel and Kingston, this rather attractive SSD displays good performance, except possibly write large files, but it cost 340 euros, makes it much too expensive to Given the low storage space offered only 80 GB

As for the OCZ range, if the solid series is sort of our tests so honorable, given its price, we will be more circumspect on the Apex. Incorporating a mechanism based on two controllers to operate the disk as a RAID performance is not honest to go, especially when it comes to read or write files small.

How can we not conclude on the issue of cost? Because of course the SSD technology at a cost still too high! When a hard disk with a capacity of 1 terabyte trades 80 new in the euro, the tenth offering SSD for storage space is sold three to four times more expensive! A significant difference too, which confines the SSD market to a still small. We bet that the situation will evolve slowly but surely!

Frankly to say, I like where this thread is very interesting to discuss.

[shailesh_akola]

what about data security and retrival. From normal hard disk drives having magnetic material the HDD drives arent more reliable?
That means if circuit or Chips get damaged due to power or some other reason the data is not affected as it is on platter.
So how reliable are SSD 's ?
Shailesh

[geekboy]

Originally Posted by shailesh_akola

what about data security and retrival. From normal hard disk drives having magnetic material the HDD drives arent more reliable?
That means if circuit or Chips get damaged due to power or some other reason the data is not affected as it is on platter.
So how reliable are SSD 's ?
Shailesh

Yes, there is a higher risk of mechanical breakdown in digital signage players using HDD, and a small glitch is all it takes to bring down an entire digital signage network. When data is retrieved from a hard disk drive, the motor needs to start so the platters can spin and the heads can read the data. All of those mechanics take time, which makes data retrieval from an HDD much slower than from an SSD.