If we had an award for most improved in the SSD space, it would have to go to Samsung. When we first encountered Samsung MLC drives a few years ago they were pretty bad. Prices were high and performance was low. Samsung offered no end-user upgradable firmware for those early drives either, although that was eventually rectified. The first Samsung MLC SSDs were reliable, they just weren't worth the money when you had much better options from companies like Intel.

Samsung had all of the right pieces for success however. Like Intel, Samsung made its own NAND, controller and wrote its own firmware. Unlike Intel, Samsung stuck to the vertically integrated formula.

I remember arguing with Samsung engineers a few years ago about the importance of random IO performance compared to sequential speed. I remember feeling like they were making the same mistake that all SSD makers were making back then: heavily prioritizing sequential IO when it was a failure to deliver good random IO performance as well that really hurt SSD adoption. Although the first Samsung SSDs weren't very good, they got better over time. While the first generation couldn't be recommended, the Samsung SSD 470 could. It still wasn't our favorite drive, but it finally brought performance up to a reasonable level. Last year's 830 release showed us that Samsung woke up. Today, Samsung is adding two new members to the family: the Samsung SSD 840 and the 840 Pro. The former is the first productized consumer SSD to use Samsung's 21nm 3-bit-per-cell MLC (aka TLC) NAND, while the latter is Samsung's new flagship drive using 21nm 2bpc MLC NAND.

Unfortunately we don't have samples of the unique TLC SSD 840, just the MLC 840 Pro. Despite the use of TLC NAND, Samsung claims the vanilla 840 should offer similar performance to the current 830. Samsung also claims that endurance should be reasonable for consumer workloads.

The 840 Pro should be tangibly faster than the 830 thanks to a new controller, new firmware and new NAND:

Samsung SSD 840 Pro vs 830
  Samsung SSD 830 (256,512GB) Samsung SSD 840 Pro (256,512GB)
Sequential Read 520MB/s 540MB/s
Sequential Write 400MB/s 450MB/s
Random Read 80K IOPS 100K IOPS
Random Write 36K IOPS 78K IOPS
Active Power Use 0.24W 0.068W
Idle Power Use 0.14W 0.042W

While the 830 used Samsung's 27nm MLC NAND, the 840 Pro uses Samsung's latest 21nm MLC NAND. The move to 21nm will eventually drive NAND pricing lower, although today Samsung expects price parity between the TLC equipped 840 and the old MLC 830. The 840 Pro should sell for a 25 - 30% premium over the current 830.

Samsung SSD 840 Pro Pricing
  64GB 128GB 256GB 512GB
Samsung SSD 840 Pro $99.99 $149.99 $269.99 $599.99

The move to 21nm is also coupled with a move to a 400Mbps Toggle 2.0 NAND interface. Block and page sizes remain the same for 2bpc MLC 21nm NAND, and maximum capacity per die is still 8GB. Although beyond the scope of this article, 3bpc TLC 21nm NAND sees 50% slower program/erase times compared to the 2bpc MLC 21nm NAND.

Both the 840 and 840 Pro use Samsung's 4th generation SSD controller. Samsung's MAX controller was used in the SSD 470, its successor, the MBX controller, wasn't used in retail drives, while MCX debuted in the 830 and MDX is in the 840/840 Pro. The basic architecture of the controller hasn't changed. Internally there are three ARM9 cores now running at 300MHz. Update: Samsung originally listed ARM9 cores but has since told us that there are three ARM Cortex R4s inside of the new MDX controller.

The MDX controller features a hardware AES-256 encryption engine that's managed using a system BIOS password like most other drives in this class.

The MDX controller is paired with 512MB of LPDDR2-1066 in the Samsung SSD 840 Pro, doubling up the DRAM used in the 830 as well as increasing bandwidth to DRAM by 33%:

SSD DRAM Size Comparison
Drive Controller DRAM Size DRAM Speed
Corsair Neutron GTX LAMD LM87800 256MB DDR2-800
Crucial m4 Marvell 88SS9174 256MB DDR3-667
Intel SSD 320 Intel X25-M G3 64MB SDR-166
Intel SSD 520 SandForce SF-2281 0MB -
OCZ Vertex 4 Indilinx Everest 2 512MB/1GB DDR3-800
Samsung SSD 830 Samsung MCX 256MB DDR2-800
Samsung SSD 840 Pro Samsung MDX 512MB LPDDR2-1066

The 840 Pro will be available in 64 - 512GB capacities. Although the controller supports up to 1TB of NAND, Samsung believes that the ultra-high-density NAND required to hit 1TB is too cost prohibitive at this point. Spare area is set at around 7% by default, although users will be able to adjust it via Samsung's SSD Magician utility. The vanilla 840 on the other hand will boast more spare area (likely to help manage endurance on the TLC NAND) and will launch at 120GB, 250GB and 500GB capacities as a result.

The 256GB SSD 840 Pro features 8 x 32GB NAND devices on the front of the PCB and nothing on the back

The 840 comes with a 3 year warranty compared to a 5 year warranty on the 840 Pro.

The 840 Pro drops the brushed aluminum look of the 830 for slightly more modern, flat black styling. The drives will be available in a 2.5" 7mm form factor, similar to the 830.

Samsung SSD 840 Pro (top) vs. Samsung SSD 830 (bottom)



Both drives will be available on October 15th, however in advance of the release Samsung provided us with a beta sample for review. We were only able to get a 256GB 840 Pro initially but we've already asked Samsung for additional capacities. The other bad news is after running through our client test suite and preparing the drive for a run through our enterprise suite, our pre-production sample died. This isn't the first time we've had an SSD die during our test process, pretty much every company has seen a failure during one of our reviews, but despite Samsung's excellent track record even it isn't immune from early issues. These drives are a few weeks away from retail and Samsung will be getting our sample back this week to figure out what went wrong.

Update: My replacement 840 Pro also died, I have shipped both drives back to Samsung and are waiting for their analysis of the failures. 

Update 2: It looks like this may have been a firmware issue. Retail drives should ship with fixed firmware.

The Test


Intel Core i7 2600K running at 3.4GHz (Turbo & EIST Disabled) - for AT SB 2011, AS SSD & ATTO


Intel DH67BL Motherboard


Intel H67

Chipset Drivers:

Intel + Intel RST 10.2

Memory: Corsair Vengeance DDR3-1333 2 x 2GB (7-7-7-20)
Video Card: eVGA GeForce GTX 285
Video Drivers: NVIDIA ForceWare 190.38 64-bit
Desktop Resolution: 1920 x 1200
OS: Windows 7 x64


Random & Sequential Performance
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  • nextel2010 - Tuesday, September 25, 2012 - link

    I couldn't agree more. I have two Samsung 830's, and they have been bulletproof. I used them to replace two Intel 520's, one of which was BSODing several times a day, and the other intermittently, both on previously stable systems. The SF-2281 controllers on those still need work, in spite of Intel's best efforts to date. The 830's have reliable, proven controllers. In practice, they are as wicked fast as the 520's. I never regretted switching over from Intel. While the 840's are likely to take the performance crown, to me, the 830 is fast enough, and new controllers make me nervous. Give me a year of proven stability, and I'll consider switching (of course, the 850 will be out by then...).
  • FunBunny2 - Tuesday, September 25, 2012 - link

    The only problem with waiting a year: with Moore still in control (mostly, really, integration) controllers go out of style in a year. I wonder how long any stable manufacturers (let alone the likes of OCZ) will still have a controller 3 or 5 years out?

    IOW, just as we don't really need the "improved" iPhoneX every so often, the same is true in the SSD space. It's planned obsolescence.
  • Old_Fogie_Late_Bloomer - Tuesday, September 25, 2012 - link

    After moving my Steam folder from my SATA II Intel 320 160Gb to my SATA III Samsung 830 64GB and seeing basically no difference in load times, I have to say that I'll probably keep my eyes peeled for deals on the 830, rather than jumping on the 840. If I could get a 512GB for my laptop for under $400, I'd jump on it and not worry about the difference in performance.
  • HisDivineOrder - Wednesday, September 26, 2012 - link

    Agree on the massive discount, but... so far I haven't seen a "massive discount." The 256gig drive I've been eyeing has been hovering around the $200 price point for a long time now. That's not massive to me. Newegg priced it once for $180 and that was pretty decent for a "massive" discount, but they only did that twice and haven't done it in a long while (ie., since I had the cash to invest).

    This is especially relevant when I expect the 840 Pro to drop around that point ($200-ish) once supply matches demand within a couple of months. I'm not interested in beta testing TLC for Samsung either.

    And I'd probably pay an extra $20 ($220) to have the superior performance/perf per watt of the 840 when push comes to shove.
  • dananski - Monday, September 24, 2012 - link

    Very impressive indeed. Quite a decent improvement on their main performance competitor - their own 830. Don't think it'll be necessary to upgrade from said 830 in my desktop, since that is lovely and fast already, though with the far lower power consumption this could be an ideal laptop upgrade for pretty much anyone :)
  • Eeqmcsq - Monday, September 24, 2012 - link

    Mmm... bumping up against that SATA 6 Gbps wall. I can't wait for SATA Express to bust through this wall. I know the faster interface won't make much difference for typical real-world use cases, but SSD performance has increased so quickly over the past few years, I don't want to see its progress slowed by an interface bottleneck.
  • iwod - Monday, September 24, 2012 - link

    Yes we really need those quick. And hopefully straight to PCI-E 3.0 as well so it would provide us a true Bi-Directional 2GB/s

    I think we will hit diminishing of returns once we hit that high numbers with the current software.
  • nathanddrews - Monday, September 24, 2012 - link

    While a 2GB/sec sequential access would be awesome - no disagreement there - it won't feel like much of an upgrade without a significant gain in random IO. A drive that hits the 6Gbps peak in random 4K access would impress me more.
  • Grok42 - Monday, September 24, 2012 - link

    Whatever the next interconnect is, I hope they build it for the next 10 years. I'm tired of all these incremental improvements requiring different cables. Maybe I've just been building computers too long?
  • Denithor - Tuesday, September 25, 2012 - link

    SATA Express isn't going to require a different cable. Go read the article for more details.

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