Last month, Samsung held its annual SSD Global Summit in Seoul, South Korea. More than 100 journalists from around the world were present. Tom's Hardware sent its U.S. and German teams to learn more about the company's 840 EVO, which we reviewed in Samsung 840 EVO SSD: Tested At 120, 250, 500, And 1000 GB, a handful of drives that aren't available yet, and upcoming storage technologies expected to dramatically change the performance characteristics of next-gen devices.

　　The summit began with a little background on Samsung. This shouldn't come as a surprise to anyone who has ever purchased an SSD, a phone, a notebook, a TV, a refrigerator, built an oil refining plant, or insured a car in South Korea, but Samsung is a very big conglomerate with many different businesses. It pulled in more than $180 billion dollars in revenue last year.

　　There's no way to attribute the company's success to any one industry, but heavy investment in NAND research and production is certainly a big reason why it's doing so well in the semiconductor space.

　　Consider the sheer magnitude of current and future NAND shipments. In 2013, there will be 40 billion gigabytes of flash that ship out, or 40 EB (exabytes), a four with 19 zeroes behind it. At a compound annual growth rate (CAGR) of 45%, NAND shipments should hit 140 EB by 2016.

　　Of course, not all of that NAND is destined for SSDs. Only 16% of it went into solid-state drives last year. By 2016, Samsung predicts that number will rise to nearly 26%, with the majority of flash memory going into mobile phones.

　　The market share numbers give us a pretty telling story about Samsung's position in this space.

　　As of 2012, Samsung claimed 40% of the total NAND market. It's a familiar position for the company, which has held that crown for the past 11 years.

　　When you break down the SSD forecasts according to segment, it's clear that the PC space dominates. The enterprise-oriented server storage market isn't as large, naturally. But it's expected to grow over the next several years.

　　Samsung says its drives will be in six out of every 10 PCs that ship in 2013. Solid-state drives like the 840 Pro grab headlines, but it's the company's OEM business moving volume. The most recent example is Apple's MacBook Air featuring a Samsung-manufactured PCI Express-based SSD that caught a lot of people by surprise.

　　During our time at Samsung's SSD Summit, we looked at (but didn't touch) technologies that the company is expected to introduce over the next year. Like many of its competitors, Samsung is is investing heavily in next-generation protocols, physical interfaces, and form factors. PCI Express is where the company sees storage moving to next. 

　　We've reviewed several PCI Express-based cards over the last year. Many of them were simply conventional SATA drives, bridged to communicate over PCI Express. The result was often very fast, but still dependent on SATA and AHCI. That's going to change in 2014, though.

   

　　Pictures are always worth a thousand words, right? Think of the physical connection and protocol like the lanes on a highway. SATA has a fairly restrictive limit on the number of pathways data can take. PCI Express is far more scalable, and you're able to combine lanes to create larger links, depending on the performance your application demands.

   

　　As protocols go, we've relied on AHCI for many years. The problem is that it was designed with spinning disks in mind, and not SSDs. As a result, we're already slamming up against the SATA interface's limits. In an effort to standardize solid-state drive access across PCI Express, 80 companies (led in part by Samsung), created the Non-Volatile Memory Host Controller Interface Specification. NVM Express, as it's called, is the first interface designed specifically with SSDs in mind.

  

　　The above slide has a lot of low-level detail describing NVMe, but there are two important points. First, AHCI adds an enormous amount of overhead and latency to commands and transfers, which simply aren't required when you're working with flash memory. The second one involves queuing. The AHCI protocol can only handle one queue with up to 32 commands. Even the fastest 15,000 RPM disk drives have access times in 5 ms range. Hammered by purely random accesses, a single queue with 32 commands is more than enough.  

　　When it comes to solid-state storage, though, parallelism can almost be limitless. Most client-focused architectures employ eight-channel designs, but there's nothing preventing more complex controllers. In enterprise applications, specifically with PCIe add-in cards, the number of channels and NAND packages can be much higher. NVMe allows for 64,000 queues and 64,000 commands per queue! 

　　We've been patiently waiting for the first NVMe-based hardware since the specification was released in early 2011. As you can see from Samsung's roadmap, the wait is almost over. 

　　Earlier this year, Samsung announced its XP941. While this M.2-compliant drive is connected through a two-lane PCI Express link, it still relies on AHCI. It's intended for Ultrabooks and may not be sold in retail channels. At least in the client space, we'll need to wait for the XP941's successor before getting introduced to NVMe.

　　The news is more promising on the enterprise side. Samsung announced its XS1715, which is NVMe-based.

　　In fact, the XS1715 is the first 2.5" SSD employing NVMe and an SFF-8639 connector (set to become the de facto for enterprise connectivity). The drive's high-density interface facilitates SATA, dual-port SAS, or third-gen PCIe x4 with accompanying reference clock and sideband signals. This product's specifications are truly amazing. With sequential reads rated at 3 GB/s and random reads in excess of 700,000 IOPS, it'll easily outpace most of today's PCI Express-based add-in cards.

　　All of that performance in a 2.5" enclosure with reportedly low power consumption should garner a lot of attention from enterprise customers. Unfortunately, Samsung was tight-lipped on availability and pricing.

　　As we know, Samsung is in a unique position as an SSD manufacturer. The fact that it fabricates its own NAND means the company can cherry-pick the very best flash for those 840 Pros. It's also pushing the envelope with regard to lithography in a way that very few competitors can match. Consequently, Samsung's engineers also know where those solid-state drives come up short, giving them a problem to work on solving.

　　When you look at the spec sheet for pretty much any SSD family, you notice that the maximum performance levels are typically available from the highest-capacity models. At lower capacities, those throughput numbers trail off pretty fast. In fact, many drives under 100 GB bashfully offer sequential write rates in the low 100 MB/s range. Why? Usually, it comes down to the number of dies per memory package, and the controller's ability to utilize them all in parallel. As the density of flash increases, you need fewer dies to hit certain capacity points, and that can detract from performance. SSD vendors can use lower-density NAND for as long as it's still available, but that also drives prices up, which nobody likes.

　　This conundrum is exacerbated by triple-level cell flash. Capable of storing three bits for every memory cell, TLC NAND further increases density and reduces cost compared to MLC flash with two bits per cell. The price you pay is higher latency. TLC NAND takes longer to stabilize, which affects its performance.  

　　To combat those compromises, Samsung introduced us to a couple of new technologies. The first is called Turbo Write. Think of this as an additional tier of storage space between the system RAM and TLC NAND. In effect, Samsung takes a small amount of the triple-level cell flash and treats it like SLC, or single-level cell memory. This reduces latency significantly, augmenting performance so long as the data you're working with is in that space.

　　Turbo Write increases performance across all capacity points, though the 120 GB configuration enjoys the largest boost. Claimed to improve sequential throughput by as much as 3x, this feature is key to extracting respectable benchmark numbers from a low-cost, lower-capacity SSD.

　　Samsung based the amount of NAND dedicated to Turbo Write on typical desktop workloads, it said. Even in the entry-level space, the 120 GB 840 EVO can maintain those impressive numbers across 3 GB of writes. That's more than enough for most folks. If you do routinely write more than that at a time, you might want to consider a true enthusiast-oriented SSD like the 840 Pro or one of its competitors.

　　While Turbo Write is a feature that you can almost always take advantage of, Dynamic Thermal Guard is something that you hope to never use. Almost every SSD not specified for industrial applications has an operating range between 0 and 70 degrees Celsius. High temperatures can cause a number of issues with NAND, from lower write endurance to bit errors.

　　So, when Dynamic Thermal Guard picks up temperatures in excess of 70 degrees, it cuts back on write performance to reduce power consumption and, consequently, heat until the drive falls back into a safer thermal range. SSDs certainly aren't indestructible. They consume power, dissipate heat, and typically require airflow over their enclosures. This feature should help safeguard an SSD's sensitive components, even if the other parts in your PC are aggressively overclocked.

　　Finally, Samsung showed of the spoils of its 2012 acquisition of data caching company Nvelo. It's RAPID software-based feature allows the Samsung's SSDs to cache hot data in host memory to accelerate I/O. The performance improvements it showed off on-stage (and we later demonstrated on this page of our 840 EVO review) were outstanding.

　　The demo we saw in Seoul had read performance jump over 750 MB/s, while writes more than doubled to 1100 MB/s. Even though Windows already caches writes, RAPID takes this to another level entirely. It does come at a cost, though. RAPID uses up to 1 GB of host memory, though that number is dynamic and depends on the amount of RAM available. When asked about the possibility of power loss, David Lin, vice president of product management for RAPID, conceded that data could be compromised. He then tempered our concern somewhat by adding that RAPID responds to operating system flush commands, which are issued regularly.

　　RAPID is currently only enabled in Windows, but will be available for all 840-series drives once Samsung's Magician 4.2 software is released.

　　We're glad to see Samsung investing heavily in innovative ways to boost storage performance, and not just relying on its most obvious advantages over other companies. It's latest features aren't necessarily exclusive; however, when you combine them with a proprietary controller, the company's own flash, and planned firmware updates, it's clear to see that Samsung isn't resting on its laurels.

　　When Samsung launched its 840 last year, the technical press expressed concern about the write endurance of triple-level cell memory. A number of folks seemed to think that a 1000 program/erase-cycle rating meant that the 840s would start failing after a few months. Of course, we've seen that those fears were largely exaggerated. The general sentiment toward TLC NAND remains, though. Many readers who know what triple-level cell memory is, but haven't spent any time testing it, tend to distrust the technology.

　　If you don't think your comments are being read at a company as large as Samsung, you are mistaken.

　　At last year's SSD Global Summit, Samsung was very coy about its triple-level cell NAND. It didn't even want to talk about lithography. During one Q&A session with company executives, the same questions were asked multiple times before Samsung gave up some answers. Write endurance inquires were deftly deflected, too. Everyone in the room already knew that Samsung's TLC NAND was rated for ~1000 program/erase cycles, but the execs refused to confirm. They tried claiming the company's TLC-based products were on par with SSDs built using two-bit-per-cell flash on the same node. Confidence was not inspired by those responses.

　　This year, however, Samsung went on the offensive with TLC NAND. Even our own storage team had already taken 840s over 3000 P/E cycles before sectors started getting reallocated. So, Samsung showed us the math on how much data has to go through an 840 before it's at risk of failure. By the end, it appeared that everyone in the room believed an 840 (or 840 EVO now) offers enough write endurance headroom for most desktop applications.

　　As Tom's Hardware's enterprise storage editor, I discuss endurance in each of my stories. Business workloads can be downright hostile to solid-state storage. I'm talking random writes, 24 hours a day. In many applications, even eMLC NAND rated for 35,000 P/E cycles is inadequate. I've personally exhausted more MLC-based drives than I care to even think about. But I'm also a client user. I write stories, render video, edit pictures, and compile code. I've been using SSDs for years without ever measuring I/O on my personal workstation. 

　　What did I find when I pulled up that data? Apparently, I don't write very much to my drive. On an SSD that was in my system for two years, I had written a total of 2 TB. At that rate, Samsung's 120 GB 840 would last me more than 120 years, while the 250 GB model would have the write endurance to go 250 years. Even with write amplification factored in, you're looking at plenty of time beyond the three year warranty. 

　　Perhaps what Samsung knew all along was that write endurance doesn't tell the whole story of reliability. Yes, the company's triple-level cell flash has about one-third of today's MLC NAND. But does that really matter? With sales greater than 2.5 million units in 10 months, a lot of customers either don't think so or don't know any different.When Samsung sold its hard drive division to Seagate back in 2011, it made a clear statement about where the company thought storage was heading. Even though SSDs only account for 10% of the total market, growth over the next few years is expected to be explosive. Samsung is already snatching more volume today than any other manufacturer, and it's trying to set itself up for an even more dominant role in the SSD space.

　　There are also areas in Samsung's portfolio that are conspicuously empty, specifically the PCI Express-based add-in cards. Most other companies have high-performance options able to transcend the limitations of SATA, and we were expecting Samsung to talk about something similar. No dice, though. Other products, like the XP941, are destined for OEM customers and may never touch retail shelves. The company may be holding off until it's confident in its ability to lead the field. But for the time being, Samsung has a way to go before its solid-state line-up is truly comprehensive. This is going to hurt most in the enterprise space, where customers want a one-stop shop. Only time will tell whether methodical steps forward will pay off.

　　Some people care only about price and performance when they buy an SSD. Samsung has something for them. Others prioritize reliability above all else. After learning the hard way to talk openly about the hardware in its drives, the company is a little more confident talking about the components it uses. And now, after we've done plenty of write endurance testing on our own time, we don't have the same trepidation about TLC NAND. So that second group should be happy with Samsung's newest SSDs, too. This company still has a very OEM-oriented mindset, but we've watching it evolve and can see a marked difference in how it operates today.

　　Between Samsung's annual SSD summit, a newly-announced developer's conference, and a willingness to participate in Tom's Hardware's own "Ask Me Anything" series, Samsung is showing a level of transparency we haven't seen from it before. Pile that on top of good old fashioned innovation, and we wouldn't be surprised if your next SSD turns out to be an 840 Pro, 840 EVO, or something based on Samsung's next-gen interface efforts.