VideoCards says reference-based cards will be clocked at up to 2.3GHz, with custom models from AMD's AIBs offering up to 2.4GHz. The site also heard that a cut-down version (Navi 21 XL) will be clocked around 2.2GHz.
All three variants (XTX, XT and XL) would feature 16GB GDDR6 memory across a 256-bit interface. The Big Navi card are to feature a special cache, possibly codenamed Infinity Cache, however, the details on its operation are still scarce.The official reveal from AMD is expected on October 28th, with availability expected sometime in November.
Navi 21 XT— Patrick Schur (@patrickschur_) October 17, 2020
~2.4 GHz (Game Clock)