Hybrid Memory Cube

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Hybrid Memory Cube (HMC) is a high-performance RAM interface for through-silicon vias (TSV)-based stacked DRAM memory competing with the incompatible rival interface High Bandwidth Memory (HBM).

Overview

Hybrid Memory Cube was announced by Micron Technology in 2011[1] and promises a 15 times speed improvement over DDR3.[2] The Hybrid Memory Cube Consortium (HMCC) is backed by several major technology companies including Samsung, Micron Technology, Open-Silicon, ARM, HP, Microsoft, Altera, and Xilinx.[3]

HMC combines through-silicon vias (TSV) and microbumps to connect multiple (currently 4 to 8) dies of memory cell arrays on top of each other.[4] The memory controller is integrated as a separate die.[1]

HMC uses standard DRAM cells but it has more data banks than classic DRAM memory of the same size. The HMC interface is incompatible with current DDRn (DDR2 or DDR3) implementations.[5]

HMC technology won the Best New Technology award from The Linley Group (publisher of Microprocessor Report magazine) in 2011.[6][7]

The first public specification, HMC 1.0, was published in April 2013.[8] According to it, the HMC uses 16-lane or 8-lane (half size) full-duplex differential serial links, with each lane having 10, 12.5 or 15 Gbit/s SerDes.[9] Each HMC package is named a cube, and they can be chained in a network of up to 8 cubes with cube-to-cube links and some cubes using their links as pass-through links.[10] A typical cube package with 4 links has 896 BGA pins and a size of 31x31x3.8 millimeters.[11]

The typical raw bandwidth of a single 16-lane link with 10 Gbit/s signalling implies a total bandwidth of all 16 lanes of 40 GB/s (20 GB/s transmit and 20 GB/s receive); cubes with 4 and 8 links are planned. Effective memory bandwidth utilization varies from 33% to 50% for smallest packets of 32 bytes; and from 45% to 85% for 128 byte packets.[4]

As reported at the HotChips 23 conference in 2011, the first generation of HMC demonstration cubes with four 50 nm DRAM memory dies and one 90 nm logic die with total capacity of 512 MB and size 27x27 mm had power consumption of 11 W and was powered with 1.2 V.[4]

Engineering samples of second generation HMC memory chips were shipped in September 2013 by Micron.[2] Samples of 2 GB HMC (stack of 4 memory dies, each of 4 Gbit) are packed in a 31×31 mm package and have 4 HMC links. Other samples from 2013 have only two HMC links and a smaller package: 16×19.5 mm.[12]

The second version of the HMC specification was published on 18 November 2014 by HMCC[13]

Systems incorporating HMC are expected to ship in 2015.[14]

JEDEC's Wide I/O and Wide I/O 2 are seen as the mobile computing counterparts to the desktop/server-oriented HMC in that both involve 3D die stacks.[15]

See also

References

  1. ↑ 1.0 1.1 Micron Reinvents DRAM Memory // Linley group, Jag Bolaria, 12 September 2011
  2. ↑ 2.0 2.1 Lua error in package.lua at line 80: module 'strict' not found.
  3. ↑ Microsoft backs Hybrid Memory Cube tech // by Gareth Halfacree, bit-tech, 9 May 2012
  4. ↑ 4.0 4.1 4.2 Hybrid Memory Cube (HMC), J. Thomas Pawlowski (Micron) // HotChips 23
  5. ↑ Memory for Exascale and ... Micron's new memory component is called HMC: Hybrid Memory Cube by Dave Resnick (Sandia National Laboratories) // 2011 Workshop on Architectures I: Exascale and Beyond, 8 July 2011
  6. ↑ Micron's Hybrid Memory Cubes win tech award // by Gareth Halfacree, bit-tech, 27 January 2012
  7. ↑ Best Processor Technology of 2011 // The Linley Group, Tom Halfhill, 23 Jan 2012
  8. ↑ Hybrid Memory Cube receives its finished spec, promises up to 320GB per second By Jon Fingas // Engadget, 3 April 2013
  9. ↑ HMC 1.0 Specification, Chapter "1 HMC Architecture"
  10. ↑ HMC 1.0 Specification, Chapter "5 Chaining"
  11. ↑ HMC 1.0 Specification, Chapter "19 Packages for HMC-15G-SR Devices"
  12. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  13. ↑ Hybrid Memory Cube Consortium Advances Hybrid Memory Cube Performance and Industry Adoption With Release of New Specification, 18 November 2014
  14. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  15. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  16. ↑ Lua error in package.lua at line 80: module 'strict' not found.

External links

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