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Transcend SSD720 120 GB

Being larger and more renowned than Silicon Power, Transcend was started up in the late 1980-ies and has been focusing on memory-related products ever since. Of course, Transcend couldn’t help producing devices with NAND flash memory which are so popular nowadays. Like Silicon Power, Transcend has selected the SandForce platform, taking its place in the second tier of SSD makers. It means that there’s nothing original about Transcend SSDs. They are similar to many products of this class from other brands.

Currently Transcend offers two consumer-class SATA3 SSDs: SSD720 and SSD320. We’ve managed to get a senior model for our tests. Its packaging provokes no emotions. There’s a lot of captions around the black cardboard box which give you information about the product, both useful and not. The box is somewhat thicker than is usually the case with SSD packaging.

 

This doesn’t indicate some extra accessories, though. In fact, there’s nothing in the box except the SSD and its user manual. There is even no adapter to install it into a 3.5-inch bay of a system case. The interior of the box is just filled with air and the plastic wrap that protects the SSD from damage during transportation.

The SSD itself is an aluminum brick, powder-coated in the popular “wet asphalt” style. The height of the brick is 7 millimeters which means that the Transcend SSD720 can be used in ordinary computers as well as ultrabooks.

 

The sticker on the top of the case tells you the model’s name, part number and capacity. Overall, the Transcend SSD720 looks like many other same-class products.

There’s nothing exciting inside, either. Featuring an original design, the PCB carries a standard set of components: an LSI SF-2281 controller on one side and eight SanDisk SDZNPQBHER-016GT chips on the other side. In other words, the Transcend SSD720 has the same hardware configuration as the above-discussed Silicon Power Velox V60.

 

The second-generation SandForce platform employed in the Transcend SSD720 uses 24nm flash memory with Toggle Mode interface. The SanDisk chips have two 64-gigabit semiconductor dies each, so the controller can use 2-way interleaving on each of its eight channels in this 128GB SSD. From the hardware standpoint, the Transcend SSD720 is similar to the numerous SandForce-based products with synchronous memory from IMFT. Similar, but not identical.

Now let’s take a look at the official specs of the Transcend SSD720 128GB:

  • Controller: SandForce SF-2281;
  • Interface: SATA 6 Gbps;
  • Flash-memory: synchronous 24 nm Toggle Mode NAND;
  • Size: 128 GB;
  • Cache-memory: none;
  • Sequential read speed: up to 560 MB/s;
  • Sequential write speed: up to 540 MB/s;
  • Random write speed (4 KB blocks): up to 93000 IOPS.

The specified speeds are indecently high and, considering the peculiarities of the SandForce controller, have little to do with reality. What’s interesting about them is the specified capacity. It is no typo: the storage capacity is 128 rather than 120 gigabytes.

Transcend engineers have somehow found an extra 8 gigabytes in the standard design of SSDs with SF-2281 controller. The amount of reserved space is reduced from 13 to 7%, which looks like a competitive advantage of the Transcend SSD720 over the Silicon Power Velox V60 despite the same hardware.

Transcend didn’t use some special magic for that. The capacity increase is currently permitted by the reference SandForce firmware. SSDs with SF-2281 controller used to reserve some of their flash memory for two purposes: 1) replacement memory cells and garbage collection and 2) RAISE technology. It is impossible not to lose some of the SSD’s total capacity in the first case, so there are actually no SSDs available that offer all of their flash memory to the user. As opposed to that, the RAISE technology can now be turned off and it is indeed turned off in the Transcend SSD720.

RAISE is a feature of second-generation SandForce controllers which improves reliability by adding checksums to data that help in error correction. It is similar to RAID5 but is applied to NAND flash devices rather than hard disks. The technology needs one unused NAND device to work, which explains the capacity reduction typical of SandForce-based SSDs. One semiconductor die (8 gigabytes) is used to store the checksums. The controller instead acquires the ability to correct errors and even prevent data loss in case of a failure of a whole NAND device.

RAISE is useful in two cases. First, it’s when high reliability is required, for example in corporate environments. Second, it’s when the SSD uses low-grade flash memory which can produce a lot of errors. As soon as the SandForce firmware permitted to disable RAISE, there appeared RAISE-less solutions like the Transcend SSD720. SanDisk’s 24nm flash installed in this SSD is high quality and needs no special technology for error recovery.

The Transcend SSD720 has one more unique feature. The manufacturer provides a special utility called SSD Scope for it. Its extensive functionality can only be matched by Intel’s SSD Toolbox.

SSD Scope can give you information about the drive and its S.M.A.R.T. status.

It can update the firmware, too. Besides that, it can control the OS’s TRIM command and clone data from an HDD to an SSD.

Some of the utility’s features are not implemented properly, though. For example, you can clone only to a larger partition, which isn’t a likely scenario with SSDs. SSD Scope is also supposed to support diagnostic scanning and Secure Erase, but these features didn’t work with our SSD720 120GB drive.

Transcend’s attention to the software part of this product can also be seen in regular firmware updates. The SSD720 can already be used with firmware version 5.0.4 which has been adapted for but a small number of SandForce-based products so far.

 
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