At Samsung Tech Day 2022,Samsung announced GDDR7 as the successor ofGDDR6X, which could deliver up to 36 GT/s.[1] Samsung announced two months later that it would usePAM-3 signaling to achieve the highest transfer rate.[2]
On March 8, 2023,Cadence announced the verification solution tool for preliminary GDDR7SDRAM production.[3]
On June 30, 2023,Micron announced that it will be manufactured using 1β node (equivalent to12–10 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 (100% higher bandwidth per pin compared to 16 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 useepoxy molding compound (EMC) along withIC 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 to15–14 nm[6]) 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.[7]
On March 5, 2024, JEDEC published the GDDR7 Graphics Memory formal standard and specifications.[8]
GDDR7 SDRAM uses three-level (−1, 0, +1)pulse-amplitude modulation (PAM-3), replacing GDDR6'SNRZ and GDDR6x's PAM-4. PAM-3 transfers three bits in two cycles, while NRZ transfers one bit in one cycle. PAM-3 is 20% more energy-efficient than NRZ while running at a higher bandwidth. Manufacturing equipment will be less costly than PAM-4.[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,[11] and chip capacities up to 64Gbit - compared to GDDR6X's 16Gbit.[10]
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