A few days ago, Samsung announced work on GDDR6W memory, which will be an extension of the current standard, enabling it to offer bandwidth slightly lower compared to HBM2e type chips. However, we have known for a long time that the Korean manufacturer is also actively working on a completely new generation of VRAM, including for next generation graphics cards. We are talking about GDDR7 memory. We do not know when the new memory will go into mass production, but Samsung has announced further details related to it.
The new GDDR7 type VRAM will offer an effective bandwidth of 36 Gbps, and will also use PAM3 three-level amplitude modulation.
Samsung unveils GDDR6W memory for graphics cards, notebook chips and accelerators for the HPC/AI market
Samsung, during the International Electron Devices Meeting 2022 (IEDM22) conference, shared some interesting facts about GDDR7 memory. The new generation of VRAM type GDDR7 is to be characterized by 25% lower energy demand compared to GDDR6, and the main reason for this is to use PAM3 modulation (three-level amplitude modulation) instead of the currently used NRZ (Non-Return-To) modulation -zero). Interestingly, according to information published by Dr. Ian Cutress on Twitter, PAM3 modulation is also used by Intel with the new generation of Thunderbolt.
Micron confirms the start of production of GDDR6X VRAM with an effective bandwidth of up to 24 Gbps
The lower energy demand is also to directly affect the increase in the effective speed of GDDR7 memory – this is to reach 36 Gbps, while for GDDR6 it is 20 Gbps, and for GDDR6X – 24 Gbps. In the case of a graphics card using a 256-bit bus, the GDDR7 memory bandwidth will be 1152 GB / s, while using a 384-bit bus it will be 1728 GB / s. We don’t expect to see GDDR7 memory in upcoming graphics cards, but in 2-3 years it could already be a real prospect.
I’m not attending this one, but here’s a fascinating slide. Samsung confirms that GDDR7 uses PAM3 signaling.
NRZ is 0 or 1: 1 bit/cycle.
PAM3 is -1, 0, 1: 3 bit/2 cycle
PAM4 is 0, 1, 2, 3. 2 bit/1 cycle80G Thunderbolt will also use PAM3. https://t.co/DJ8GvIDCJi pic.twitter.com/9Yw5zdUzDU
— . (@IanCutress) December 4, 2022
Source: VideoCardz, Twitter @IanCutress