It's becoming clear that AMD's new "Big Navi" Radeon RX 6800 XT is a treat for overclockers, and that it launched with much lower engine clocks than the silicon is capable of, resulting in what is possibly the largest overclocking headroom on an AMD GPU in a long time. This has been highlighted by recent conquests of the 3DMark Fire Strike leaderboard by RX 6800 XT cards, displacing even the RTX 3090 from the top. It's becoming even more clear now just how far the RX 6800 XT can be pushed. Patrick Schur on Twitter reports that the RX 6800 XT engine clocks are capped at 2.80 GHz, which is possibly why we're yet to see anything faster than that. The upcoming RX 6900 XT, on the other hand, is a better-endowed beast.

According to Schur, the RX 6900 XT has a raised engine clocked limit to 3.00 GHz in comparison to the 2.80 GHz of the RX 6800 XT. This 200 MHz increase, coupled with the 8 additional RDNA2 compute units, should mean that the Fire Strike leaderboards will get another shake-up in December, when these cards are released to market. The memory clock on both cards is capped at 1075 MHz (real), or 17.2 Gbps GDDR6-effective, although this should depend heavily on the overclocking headroom of the memory chips. It's important to note here that neither the 3.00 GHz of the RX 6900 XT, nor the 2.80 GHz for the RX 6800 XT, are advertised clock speeds for the cards, and are achievable only by manual overclocking, in some cases employing extreme cooling solutions such as liquid nitrogen.