Because CFM is an absolutely useless value to use.
It correlates directly with cooling capacity, and that's what someone with a certain CPU & heatsink needs.
You cant' pick the right noise for everyone but the most efficient fan at 35 dba is not going to suddenly turn the worst at 38 dba.
No, there probably won't be a big inversion of the rankings, but I'll give you the example of a Noctua NF-A9x14 PWM fan I have. Up to about 1k RPMs, it's almost inaudible. Then, by just like 1.1k RPMs, it develops an annoying whine. That sort of non-linearity could potentially cause it to drop several slots in the rankings.
Then we are not in a disagreement? I don't know why you are quoting me, but we are saying the same thing. when you have an efficiency curve you can then proceed to compare at ISO power which im suggesting.
That's only useful for CPU geeks, not end consumers.
What an end consumer wants to know is how the performance & efficiency of a few similar CPU models compare,
when tested as they would actually run them. As nobody is trying to decide between an i3-14100F and an i9-14900KS, having them in the same efficiency ranking is of no
practical value. Furthermore,
nobody who cares about efficiency would buy a R9 7900X and try to configure it to match the Cinebench numbers of an i7-14700K, or vice versa. So, measuring them this way is
absurd.
It just creates fake numbers that don't really help anyone. If you're trying to provide benchmarks to help real people decide which product is the best for them, then either compare them with out-of-the-box defaults (which many people use) or sanely-tuned settings that are achievable on most setups.
You don't need iso-performance or iso-power. As I said above, it doesn't make sense to compare products of wildly different performance or power, because nobody is trying to decide between a R7 7600X vs. an i9-14900K. If you merely stick to products within the same market segment, they will naturally cluster near enough, in terms of performance and power, and then you just show people how they compare in those respects so they can make tradeoffs that align with their priorities.