A couple of months ago we reviewed JMicron's JMF667H reference design SSDs, which did relatively well in our tests especially when taking JMicron's previous SSD controllers into account. As always, reference designs are only meant for evaluation and do not make their way into retail, so today we are taking a look at Transcend's SSD340.

The SSD340 is based on the same JMF667H controller, although the firmware is an older version than what we tested in the reference design SSDs. Transcend told us that they currently have no plans to update the firmware to the newer version, which I am guessing is due to using customized firmware. It is actually quite rare that OEMs use the stock firmware as typically the OEMs request some changes and customizations, making it slower and more difficult to upgrade the firmware. I would not even be surprised if some OEMs did not upgrade the firmware to ensure product differentiation because it is obvious that OEMs do not want their low end drives to jeopardize the sales of higher cost (and profit) drives. 

Update 8/18: Apparently Transcend has released a new firmware for the SSD340. I will try to find some time to test the new firmware and will provide an update if anything changes. 

Transcend SSD340 Specifications
Capacity 32GB 64GB 128GB 256GB
Controller JMicron JMF667H
NAND Micron 128Gbit 20nm MLC
Sequential Read 189MB/s 364MB/s 530MB/s 518MB/s
Sequential Write 37MB/s 73MB/s 145MB/s 285MB/s
4KB Random Read 19K IOPS 33K IOPS 62K IOPS 67K IOPS
4KB Random Write 9K IOPS 17K IOPS 35K IOPS 68K IOPS
Idle Power 0.53W 0.53W 0.54W 0.55W
Load Power (Read/Write) 1.08W / 1.14W 1.41W / 1.33W 1.52W / 1.98W 1.63W / 3.75W
Endurance 33TB 66TB 106TB 141TB
Encryption No
Warranty Three years

The SSD340 is available in capacities ranging from 32GB to 256GB. The JMF667H actually has a capacity limit of 256GB, which also limits the SSD340 to just 256GB. We should see JMF670H make its entry later this year with support for 512GB, but until then 256GB is the highest you can go with a JMicron controller.

Like nearly all client SSDs, the SSD340 has a three-year warranty with an endurance limitation. Quite surprisingly the endurance scales with capacity, although the scaling is not exactly linear. Nowadays most client SSDs only have a single rating for all capacities, so it is pleasant to see a scalable endurance for a change. I am pretty sure many OEMs just artificially lower the spec to make sure that enterprises customers do not choose the lower profit consumer drives, as the difference between high-end client and entry-level enterprise drives is quite indeterminate (i.e. entry-level enterprise drives are usually based on client platforms).

Transcend's data sheet for the SSD340 states that the drive supports DevSleep, although there are not any actual power figures listed aside from normal idle, which are way too high for DevSleep. Since the controller supports DevSleep, I have to wonder why Transcend has not published any power figures; we'll check power later on to verify whether the SSD340 actually supports DevSleep.

Transcend uses Micron's 128Gbit 20nm NAND in the SSD340. Our 256GB review sample had a total of sixteen NAND packages (eight on each side of the PCB), meaning that each package is a single-die package with one 128Gbit (16GB) die. There is also Samsung's 256MB DDR3-1600 DRAM chip working as a cache. 

Test System

CPU Intel Core i5-2500K running at 3.3GHz (Turbo and EIST enabled)
Motherboard AsRock Z68 Pro3
Chipset Intel Z68
Chipset Drivers Intel + Intel RST 10.2
Memory G.Skill RipjawsX DDR3-1600 4 x 8GB (9-9-9-24)
Video Card Palit GeForce GTX 770 JetStream 2GB GDDR5 (1150MHz core clock; 3505MHz GDDR5 effective)
Video Drivers NVIDIA GeForce 332.21 WHQL
Desktop Resolution 1920 x 1080
OS Windows 7 x64

Thanks to G.Skill for the RipjawsX 32GB DDR3 DRAM kit

Performance Consistency & TRIM Validation
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  • ddriver - Monday, August 4, 2014 - link

    I didn't say "value".
  • Impulses - Monday, August 4, 2014 - link

    Besides, $30 32GB SD cards actually hit 45-60MB/s sequential.. Think I saw a $65 64GB PNY rated at 90/60 R/W, doesn't get any more value priced than that, unless you meant bargain bin SD cards...
  • hojnikb - Tuesday, August 5, 2014 - link

    Yeah, but sd card like that would be pretty unsuitable for running OS.
  • Impulses - Tuesday, August 5, 2014 - link

    Obviously, their random access speed sucks, he and I were just drawing a parallel to other cheap devices with sequential speeds that aren't very far off... Shoot, I've paid <$50 for 32-64GB USB 3.0 flash drives that hit 200MB/s sequential read/writes. I think any enthusiast knows sequential speed isn't ultimately why you buy a SSD (most of the time), but still...
  • willis936 - Monday, August 4, 2014 - link

    I'm pretty sure SSDs from 2009 are faster than this.
  • hojnikb - Monday, August 4, 2014 - link

    they are not.
  • ddriver - Monday, August 4, 2014 - link

    2-3 years ago was 2011-2012 :) I have a Samsung 830 128 GB which IRC came out around that time, and it is actually faster, reaching like 380 MB/sec in sequential reads.
  • ddriver - Monday, August 4, 2014 - link


    Come on AT, what is this - the stone age? You know, the time people wrote on stone tablets and editing was pretty much impossible? How about an "edit" feature?
  • jabber - Monday, August 4, 2014 - link

    I have to say as long as they push 150MBps+ with 0.XX access times most cases are covered.

    All in the access times for day to day usage, not so much the raw MBps.
  • hojnikb - Monday, August 4, 2014 - link

    its not all about access times.
    You can have a bad ssd with great access times and it will still feel slow as HDD if writes are utter garbage (you can test this by installing OS on a cheap usb drive).

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