Next-gen Nvidia GPUs could come with blazingly fast 24Gbps GDDR6X memory

The next generation of graphics cards can feature GDDR6X memory that runs at 24 Gbps. Memory maker Micron said its new 16Gb GDDR6X memory chips “have unprecedented headroom” of up to 24Gbps, although we’ve only seen these max chips at 21Gbps in the new Nvidia GeForce RTX 3090 Ti.

Compare that to the 14/16 Gbps GDDR6 memory that is in use on many GPUs today and you’ll see insanely fast memory in this latest iteration of the GDDR6X. And where else will this be put to good use than in Nvidia’s next generation of graphics cards, known as Lovelace or Ada.

It’s possible that we’ll see these high-performance 16Gb GDDR6X chips make their way to Nvidia’s next-gen Lovelace generation cards, as they’re not running to their full potential today. Micron said it has a “performance roadmap” to reach 24 Gbps.

I suspect this would be kept aside exclusively for high-end Lovelace GPUs. Cheaper, more widely available memory chips (from other vendors such as SK Hynix and Samsung) are probably still preferred for the lower high-volume cards in the price-performance stack.

It’s also likely that Nvidia is the only GPU vendor to use GDDR6X. Micron and Nvidia tend to work together on these faster memory specs – having also worked on the GDDR5X that would make its way to Nvidia’s high-end Pascal graphics cards. That doesn’t entirely rule out AMD, or even Intel, from using these chips with future high-end GPUs, but history suggests it will remain an Nvidia exclusive in the gaming GPU space.

As for non-gaming GPUs, they tend to rely on different memory technologies like HBM2E.

Here is an outline of PAM4 flagging with GDDR6X memory. Memory speed is closely tied to the integrity of these four individual signals. (Image credit: Micro)

The key to high speeds with GDDR6X is something called PAM4 signaling. PAM4, or Pulse Amplitude Modulation 4-level, is effectively a technique of retaining integrity within a signal across an electrical connection, allowing the transmission of more bits each period. The result is, ultimately, greater bandwidth.

It’s not just GDDR6X memory that uses PAM4. In fact, PCI-SIG, the consortium that develops all PCIe specifications, announced that PAM4 with the upcoming PCIe 6.0 standard.

In the meantime, you’re more likely to find the PAM4 flag inside your gaming PC with a high-end Nvidia graphics card. The RTX 3090 Ti uses these recent 16Gb chips, but you’ll find the slightly slower 8Gb chips in the RTX 3080, RTX 3080 Ti, and RTX 3090.

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