DDR DIMM Memory Modules


Graphics Double Data Rate

GDDR5 Pinout and Description

Graphics Double Data Rate DIMM [GDDR-DIMM, or GDDR DIMM] is similar to the JEDEC standard for Double Date Rate SDRAMs. This page covers the GDDR ICs, which are only found on high-end Video cards used in desktop PCs. Refer to the general Memory Module page for a more complete listing of different types of modules, manufactures and descriptions.
GDDR1 uses 2.5 volt signalling, GDDR2 uses 1.8 volt signalling.
GDDR 3 runs at up to around 1.5 times the speed of GDDR 2 but consumes half the power. DDR3 SDRAM devices offer data transfer rates up to 1600 Mbps.
Module densities range from 256MByte up to 8GByte for standard JEDEC modules.

GDDR5 PinOut and Signal Assignments
Ball Signal Ball Signal Ball Signal Ball Signal Ball Signal
- MF=0 MF=1 - MF=0 MF=1 - MF=0 MF=1 - MF=0 MF=1 - MF=0 MF=1
A2 DQ1 DQ25 G3 RAS CAS T4 DQ26 DQ2 H11 BA0 A2 BA2 A4 E13 DQ13 DQ21
B2 DQ3 DQ27 L3 CAS RAS U4 DQ24 DQ0 K11 BA2 A4 BA0 A2 F13 DQ15 DQ23
C2 EDC0 EDC3 A4 DQ0 DQ24 D5 WCK01 WCK23 M11 DQ22 DQ14 M13 DQ23 DQ15
D2 DBI0 DBI3 B4 DQ2 DQ26 H5 A9 A1 A11 A6 N11 DQ20 DQ12 N13 DQ21 DQ13
E2 DQ5 DQ29 D4 WCK01 WCK23 K5 A11 A6 A9 A1 T11 DQ18 DQ10 P13 DBI2 DBI1
F2 DQ7 DQ31 E4 DQ4 DQ28 P5 WCK23 WCK01 U11 DQ16 DQ8 R13 EDC2 EDC1
M2 DQ31 DQ7 F4 DQ6 DQ30 H10 BA3 A3 BA1 A5 G12 CS WE T13 DQ19 DQ11
N2 DQ29 DQ5 H4 A10 A0 A8 A7 K10 BA1 A5 BA3 A3 L12 WE CS U13 DQ17 DQ9
P2 DBI3 DBI0 K4 A8 A7 A10 A0 A11 DQ8 DQ16 A13 DQ9 DQ17---
R2 EDC3 EDC0 M4 DQ30 DQ6 B11 DQ10 DQ18 B13 DQ11 DQ19---
T2 DQ27 DQ3 N4 DQ28 DQ4 E11 DQ12 DQ20 C13 EDC1 EDC2---
U2 DQ25 DQ1 P4 WCK23 WCK01 F11 DQ14 DQ22 D13 DBI1 DBI2 ---

GDDR1 Bandwidth: up to 1.2Gbytes/s with a 300MHz clock,
GDDR2 Bandwidth: up to 2.0Gbytes/s with a 500MHz clock,
GDDR3 Bandwidth: up to 9.6 Gbytes/s with a 1GHz clock.
GDDR4 which is just now starting to show up provides a bandwidth of 18GHz.
GDDR5 operates at up to 5Gbps at 1.5 volts.

GDDR5 SGRAM provides a mirror function (MF) pin to change the physical location of command, address, data and WCK pins and assist in routing devices back to back. The pins affected by this Mirror Function mode are listed below.

GDDR5 operates with two different clock types. A differential command clock (CK) to where address and command inputs are referenced, and a forwarded differential write clock (WCK) where read and write data are referenced to. Being more precise, the GDDR5 SGRAM uses two write clocks, each of them assigned to two bytes. The WCK runs at twice the CK frequency. Taking a GDDR5 with 5 Gbps data rate per pin as an example, the CK clock runs with 1.25 GHz and WCK with 2.5 GHz. The CK and WCK clocks will be aligned during the initialization and training sequence. This alignment allows read and write access with minimum latency.

GDDR DIMM Memory Road Map from Qimonda
Qimonda GDDR DIMM Memory Road Map

GDDR DIMM Manufacturers

GDDR memory modules are found in desk tops, and workstations.
Some companies have discontinued GDDR1 support. Example IC package types:

GDDR DIMM Manufacturers

DIMM Sockets; DIMM/SIMM Socket Manufacturers.

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Modified 3/17/12
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