GDDR7 SDRAM explained
Graphics Double Data Rate 7 Synchronous Dynamic Random-Access Memory (GDDR7 SDRAM) is a type of synchronous graphics random-access memory (SGRAM) specified by the JEDEC Semiconductor Memory Standard, with a high bandwidth, "double data rate" interface, designed for use in graphics cards, game consoles, and high-performance computing. It is a type of GDDR SDRAM (graphics DDR SDRAM), and is the successor to GDDR6.
History
- At Samsung Tech Day 2022, Samsung announced GDDR7 as the successor of GDDR6X, which could deliver up to 36 GT/s.[1] Samsung announced two months later that it would use PAM-3 signaling to achieve the highest transfer rate.[2]
- On March 8, 2023, Cadence announced the verification solution tool for preliminary GDDR7 SDRAM production.[3]
- On June 30, 2023, Micron announced that it will be manufactured using 1β node (equivalent to 12–10 nm process node), slated to release in H1 2024.[4]
- On July 18, 2023, Samsung announced the first generation of GDDR7, which can reach up to 32 Gbps per pin (33% higher bandwidth per pin compared to 24 Gbps per pin on GDDR6), 40% higher bandwidth (1.5 TB/s) compared to GDDR6 (1.1 TB/s) and 20% more energy efficient. For packaging material, it will use epoxy molding compound (EMC) along with IC architecture optimization, which will reduce thermal resistance by 70%.[5] Later, on a Q&A session, Samsung mentioned that it will be manufactured using D1z node (equivalent to 15–14 nm) and will operate on 1.2V. A 1.1V version with reduced clockspeeds will also be made available at some point in to the future after the release of the 1.2V version.[6]
- On March 5, 2024, JEDEC published the GDDR7 Graphics Memory formal standard and specifications.[7]
Technologies
GDDR7 SDRAM employs PAM-3 signaling (three-level pulse-amplitude modulation) rather than NRZ. PAM-3 is 20% more energy-efficient than NRZ while running at a higher bandwidth. Manufacturing equipment will be less costly than PAM-4. PAM-3 processes 1.58 bits per cycle, while NRZ processes only 1 bit per cycle.[8]
GDDR7 adds on-die error correction code, error checking and scrubbing features for chip reliability, mainly useful for compute/AI use cases.[9]
Initial data rates are at 32Gbps/pin, while memory manufacturers have noted that rates up to 36Gbps/pin are readily attainable. The standard has future bandwidth up to 48Gbps/pin,[10] and chip capacities up to 64Gbit - compared to GDDR6X's 16Gbit.[9]
See also
Notes and References
- Web site: 2022-10-06 . Samsung announces 36 Gbps GDDR7 memory standard, aims to release V-NAND storage solutions with 1000 layers by 2030 . 2023-06-30 . Notebookcheck . en.
- Web site: Discuss . btarunr . 2022-12-05 . Samsung Reveals GDDR7 Memory Uses PAM3 Signalling to Achieve 36 Gbps Data-Rate . 2023-06-30 . TechPowerUp . en.
- Web site: Cadence announces first GDDR7 verification solution . 2023-06-30 . VideoCardz.com . en-US.
- Web site: 2023-06-30 . Micron could introduce GDDR7 memory chips in early 2024 . 2023-06-30 . TechSpot . en-US.
- Web site: 2023-07-19 . Samsung develops industry's first GDDR7 DRAM with 1.5 TBps bandwidth . 2023-07-31 . Notebookcheck . en.
- Web site: Smith . Ryan . Samsung Completes Initial GDDR7 Development: First Parts to Reach Up to 32Gbps/pin . 2023-07-31 . www.anandtech.com.
- Web site: JEDEC Publishes GDDR7 Graphics Memory Standard JEDEC . 2024-03-05 . www.jedec.org.
- Web site: Anton Shilov . GDDR7 Arrives: Samsung Outs World's First Chip, 32 GT/s for Next-Gen GPUs . en . . 2023-07-19 . 2023-10-06.
- Web site: Shilov . Anton . Micron's GDDR7 Chip Smiles for the Camera as Micron Aims to Seize Larger Share of HBM Market . 2024-06-09 . www.anandtech.com.
- Web site: Smith . Anton Shilov, Ryan . JEDEC Publishes GDDR7 Memory Spec: Next-Gen Graphics Memory Adds Faster PAM3 Signaling & On-Die ECC . 2024-06-09 . www.anandtech.com.
