As noticed by ComputerBase, AMD reportedly removed performance-per-watt graphs from its recent RX 7900 XTX and 7900 XT graphics card presentations that compared the cards to Nvidia's RTX 4090.
AMD's footnotes from November 15th's performance presentation state there was supposed to be a performance-per-watt slide for an RX 7900 XTX versus RTX 4090 power efficiency comparison, but AMD never presented it. The omission is made clear by the "RX-841" footnote that doesn't have a corresponding slide in the deck.
The performance-per-watt slide compared the RX 7900 XTX to Nvidia's very power-hungry GeForce RTX 4090 based on publicly disclosed peak power consumption values (TBP/TGP). AMD accidentally left this footnote in its presentation, so the decision to exclude the slide was apparently made at the last minute.
We don't have any confirmation as to why AMD decided to remove this slide, and there could be several reasons for the omission. First, AMD has said that the RX 7900 XTX competes with the RTX 4080, so a comparison to the RTX 4090 might not have made sense. Additionally, while Nvidia's 40-series cards consume prodigious amounts of energy, the new architecture is more power efficient than its predecessors, and, during gaming, the 40-series cards often consume far less energy than the full TGP.
For instance, our review of the RTX 4080 found the card's performance-per-watt to be incredibly good. It outperformed Nvidia's power-sucking RTX 3090 Ti while consuming far less power during gaming than its maximum 320W TGP allows. In fact, according to our tests, the RTX 4080 Founders Edition consumed just 221W at 1080p. Furthermore, the only workload we found that would max out the RTX 4080's power budget was Furmark combined with a GPU overclock.
Nvidia also sought to highlight that its GPUs don't pull the full TGP during gaming with its own article on the same subject, (opens in new tab) stating the RTX 4080 could hit just 251W of power consumption under average gaming conditions (albeit at 1440p resolution). This is an impressive feat considering Nvidia says its previous-gen RTX 3090 Ti consumes 398W during typical gaming workloads. This works out to a 37% power reduction for the RTX 4080, and that's not even considering the 4080's slightly faster gaming performance.
It's logical to expect AMD's forthcoming RDNA 3 GPUs to be plenty efficient and easily rival or beat the 40-series in power efficiency metrics. However, as with all launch presentations, AMD would want to ensure that its card has a healthy enough lead to highlight the advantages of its architecture. Maybe the comparison against the RTX 4090 didn't work out quite as favorably as AMD expected. Conversely, AMD may have decided that comparing the two cards based on total power ratings alone might not be the best approach, as the RTX 4090 likely doesn't pull its full TGP during gaming. Besides, the RX 7900 XTX competes more directly with the RTX 4080.
It's expected for some of the comparisons in any presentation to hit the cutting room floor; for instance, as noted by Computerbase, there is also no slide corresponding to AMD's "RX-837" footnote, and it appears that the "RX-838" footnote is missing entirely.
We'll likely never know why AMD pulled the RX 7900 XTX versus RTX 4090 power efficiency comparison, but one thing is for sure — it is missing from the deck.