Samsung, Hynix, and Micron preparing for the next generation
DDR3 SDRAM is now the standard memory for servers and workstations, but its supremacy was never assured. The introduction of Fully-Buffered DIMMs was slated as a substitute, but its high costs and power consumption heralded its doom. 1333MHz has been the top speed for servers using DDR3 during the last two and a half years, but things are about to change. A number of new product launches from Intel and AMD are leading to some faster memory from Samsung, Hynix, and Micron.
Although DDR3 was first introduced in 2007, it didn't make its way to servers until March 2009. Intel's 5500 series servers were the first to make use of DDR3's higher clocks speeds and lower power consumption, while AMD followed with its Socket AM3 quad-core Opterons, code-named "Suzuka."
AMD's FX series of CPUs using the Bulldozer core are the first to officially support DDR3-1866 at stock speeds. Although its performance was not as high as anticipated, there is a lot of interest in using the FX series in the workstation market due to ECC support in its dual channel integrated memory controller. Intel's Xeon processors are dominant in that market, but they are much more expensive.
Samsung is the largest DRAM manufacturer in the world, and is currently mass producing several DIMMs to address this opportunity. The most interesting is an 8GB unbuffered ECC DIMM (M391B1G73BH0-CMA), which uses 4Gb chips running at DDR3-1866 (PC3-14900). A fully populated AM3+ motherboard like the ASUS Crosshair V Formula would be able to address 32GB of this RAM. 4GB (M391B5273DH0-CMA), 2GB (M391B5773DH0-CMA), and 1GB (M391B2873GB0-CMA) capacities will also be available.
Hynix is currently sampling a similar 8GB ECC module (HMT41GU7MFR8C-RD), but 4GB (HMT351U7CFR8C-RD) and 2GB (HMT325U7CFR8C-RD) DIMMs are already in mass production. Micron, the last U.S.-based DRAM manufacturer, has similar products in the works as well. They declined to comment at this time, but they do have 2Gb DDR3-1866 chips in mass production. All three firms are utilizing a CAS latency of 13 at this speed.
AMD's upcoming 16 core Interlagos servers and some of Intel's Sandy Bridge-E server CPUs will feature quad-channel DDR3-1600 (PC3-12800) integrated memory controllers. This is the most lucrative market for Samsung, Hynix, and Micron. All three already have 16GB and smaller capacity ECC Registered DIMMs in mass production at that speed. Hynix is sampling a 32GB DIMM, while Micron has the only DIMMs with a CAS latency of 10.
Lower voltage (1.35v) versions of these DIMMs will be the most in demand due to their reduced power consumption. However, the largest servers will use Load Reduced DIMMS (LR-DIMMs). These are the successors to FBDIMMs, but without the problematic serial interface. In addition to the address signals normally buffered by registered DIMMs, LR-DIMMs also buffer the datalines. This allows the number of memory chips that can be used per channel to be greatly increased at the cost of additional latency. Servers using as much as 2TB of memory have been proposed using this technology.
Future server CPUs based on Ivy Bridge and Piledriver architectures are expected to make use of DDR3-1866 ECC Registered DIMMs or LR-DIMMs, and all three firms have plans for those as well. DDR3-1600 is a 20% increase in memory bandwidth over DDR3-1333, while DDR3-1866 is a 40% increase. Given the pace of memory advances in the server and workstation markets, these will have to do for the next couple of years.
[Submitted by Christo [PCD]
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