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Memory Modules Overview Spring, 2004 Bill Gervasi Senior Technologist, Netlist Chairman, JEDEC Small Modules & DRAM Packaging Committees.

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Presentation on theme: "Memory Modules Overview Spring, 2004 Bill Gervasi Senior Technologist, Netlist Chairman, JEDEC Small Modules & DRAM Packaging Committees."— Presentation transcript:

1 Memory Modules Overview Spring, 2004 Bill Gervasi Senior Technologist, Netlist Chairman, JEDEC Small Modules & DRAM Packaging Committees

2 Many Applications, Many Configurations

3 Module Configurations DDR1 –Unbuffered DIMM –Registered DIMM –SO-DIMM –Micro-DIMM New: –32b-DIMM In development: –4 Rank RDIMM DDR2 –Unbuffered DIMM –Registered DIMM –SO-DIMM –Micro-DIMM In development: –Mini-RDIMM –4 Rank RDIMM –4 Rank SO-DIMM –4 Rank Micro-DIMM –Fully Buffered DIMM –DDR3 modules All JEDEC modules include Serial Presence Detect (SPD) EEPROM for boot time detection of capabilities

4 DDR2 Speed Grading Committee approved standard speed grades: 400 MT/s200 MHzDDR2-400PC MT/s266 MHzDDR2-533PC MT/s333 MHzDDR2-667PC MT/s400 MHzDDR2-800PC Data Rate X64/x72 bit data bus * chip speed Clock SpeedChip BinModule Bin

5 DDR2 Unbuffered DIMM Same physical size as DDR1: 133 mm (5.25”) New socket –More pins… 184  240 pins –Tighter pin pitch… 1.27  1.0 mm “Same plane referencing” pinout Target markets unchanged –Workstations –Desktop PC Status: APPROVED –1 Rank x8, 2 Ranks x8, 1 Rank x16

6 DDR2 Registered DIMM Target markets unchanged –Servers –High-end Workstations New feature: Address Parity –Checks integrity of every address and command sent Status: APPROVED –1 Rank x8, 2 Rank x8, 1 Rank x4, 2 Rank x4 –With or without address parity

7 DDR2 SO-DIMM Same width, shorter than DDR1: 67.6 x 30 mm Same 200 pin socket as DDR1 –Uses 1.8V key position No longer supports x72 (ECC) or registered Target markets change from DDR1 to DDR2: –DDR1: Mobile, blade server –DDR2: Does not support blade server Status: APPROVED –2 Rank x16, 1 Rank x8, 1 Rank x16, 2 Rank x8

8 DDR2 Micro-DIMM Larger module, same footprint as DDR1: 52 x 30 mm New connector –High pin count mezzanine connector –Two part: half on motherboard, half on module –0.4 mm pitch Status: APPROVED –1 Rank x16, 2 Rank x16

9 DDR1 32b-DIMM New to DDR1… no DDR2 version yet X32 only, mm wide Ultra low cost New connector –100 pins, 1.27 mm pin pitch Target market: peripherals, e.g. printers Status: APPROVED –1 Rank x16, 2 Rank x8, 1 Rank x8, 2 Rank x16

10 What is On the Horizon? DDR2 Mini-RDIMM 4 Rank DDR1 RDIMM 4 Rank DDR2 RDIMM, SO-DIMM, & Micro-DIMM Fully Buffered DIMM DDR3 modules

11 DDR2 Mini-RDIMM New to DDR2… no DDR1 equivalent Supports x72 (ECC) and registered Larger than SO-DIMM: 82 mm New socket required –244 pins, 0.6 mm pin pitch Target market: blade server

12 4 Rank DDR1 RDIMM Doubles per-slot memory capacity to 4GB! Takes advantage of existing chip selects Requires additional signals routed on motherboard PC-3200 with a single slot CS3# CS0# CS1# CS2# Memory Controller CS3# CS0# CS1# CS2#

13 4 Rank DDR2 RDIMM Similar to DDR1 4 Rank Supports address parity Requires additional signals routed on motherboard PC with a single slot… headroom to PC2-5300? PC2-6400? CS3# CS0# CS1# CS2# Memory Controller CS3# CS0# CS1# CS2# Ad. Parity

14 4 Rank DDR2 SO-DIMM, Micro-DIMM Highest capacity modules with 4 ranks of x8 –1GB using 256Mb (32 DRAMs) –2GB using 512Mb –4GB using 1Gb Lowest power modules with 4 ranks of x16 –512MB using 256Mb (16 DRAMs) –1GB using 512Mb –2GB using 1Gb –Estimated 20-25% reduction in power over x8 Higher performance –Twice as many open pages possible Cost protection during density crossovers (like 512Mb  1Gb)

15 Fully Buffered DIMM Processor DIMMDIMM Problem - Stub Bus DIMMDIMM DIMMDIMM DIMMDIMM  Each single sided DDR2-800 DIMM capable of 6.4 GB/s  Four DIMMs capable of over 25 GB/s  Bus Topology can not deliver the bandwidth to the application  Stub bus only able to deliver the bandwidth of one DIMM  Need headroom to support DDR3

16 FB-DIMM High Speed Channel

17 DDR3 Modules Active development has begun Performance to 1.6Gbps per pin Point to point, point to 2 points Fly-by buses with controller de-skew Address, Command, Clocks Data, Strobes Controller DRAM

18 Keeping Them Straight New label: 1GB 2Rx8 PC2-5300U A1 1GB = Total module capacity 2Rx8 = Number of ranks of memory & chip width PC = Speed grade in MB/s across DIMM U = Module type (unbuffered, registered, etc.) 444 = CAS latency–tRCD–tRP performance grade 11 = SPD revision (encoding + additions) A1 = Standard board layout and revision

19 2004 Modules Summary DDR1 development continues –PC-3200 speed bumps, 32b DIMM, 4 Rank RDIMM DDR2 modules ready to roll out –UDIMM, RDIMM, SO-DIMM, Micro-DIMM DDR2 Speed Grades finalized –PC2-3200, PC2-4200, PC2-5300, PC New DDR2 modules in development –Mini-RDIMM, 4 rank R-/SO-/Micro-DIMM, FB-DIMM DDR3 modules development begun New DIMM labels assist user identification

20 Thank You ___ Q & A


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