In January, the USB-IF published a listing for the Navi 21 XTXH, a then-unknown RDNA 2-based card. At the time, we speculated that the Navi 21 could be a different SKU for the RDNA 2 series, but that did not prove to be the case. Instead, ASRock, Powercolor and Sapphire, among others, released the Navi 21 XTXH as flagship RX 6900 XT cards.
However, it seems that AMD was planning to release another RX 6900 series variant called the RX 6900 XTX. The reference model would have featured a 120 mm AIO, harking back to the RX Vega 64 Liquid Edition. It is unclear if AMD has abandoned the design, but a 120 mm AIO is much smaller than the one Sapphire uses to cool the Navi 21 XTXH in the Radeon RX 6900 XT Toxic Extreme. Alternatively, the yields of the Navi 21 XTXH may have been too low for AMD to justify producing reference cards. We are only speculating, though.
Ultimately, this may be the only time that we get to see AMD's RX 6900 XTX reference card, as we imagine that the company only produced a few of them. Videocardz believes that the card may still see a release yet, although we would have expected AMD to have announced it by now, since AIBs have already started selling the Navi 21 XTXH.