A prototype Nvidia RTX Titan Ada graphics card has emerged, boasting a fully enabled AD102 GPU with 18,432 CUDA cores and 48 GB of GDDR6 memory.https://www.notebookcheck.net/Unreleased-Nvidia-RTX-Titan-Ada-prototype-surfaces-online.946823.0.html
There is the possibility that NVIDIA resorted to GDDR6 to offer ECC memory, similar to the RTX 6000 Ada Generation card on the pro side.