https://www.techpowerup.com/320822/product-pages-of-samsung-28-gbps-and-32-gbps-gddr7-chips-go-live Samsung is ready with a GDDR7 memory chip rated at an oddly-specific 28 Gbps. This speed aligns with the reported default memory speeds of next-generation NVIDIA GeForce RTX "Blackwell" GPUs. The Samsung GDDR7 memory chip bearing model number K4VAF325ZC-SC28, pictured below, ticks at 3500 MHz, yielding 28 Gbps (GDDR7-effective) memory speeds, and comes with a density of 16 Gbit (2 GB). This isn't Samsung's only GDDR7 chip at launch, the company also has a 32 Gbps high performance part that it built in hopes that certain high-end SKUs or professional graphics cards may implement it. The 32 Gbps GDDR7 chip, bearing the chip model number K4VAF325ZC-SC32, offers the same 16 Gbit density, but at a higher 4000 MHz clock. The Samsung website part-identification pages for both chips say that the parts are sampling to customers, which is usually just before it enters mass-production, and is marked "shipping."
Looks like the high end GPUs are getting this memory sometime this year.