https://youtu.be/yDEUOoWTzGw?t=731
> The 7970X required 3.6 min making the 7980X [2.2 min] 39% faster for about 100% more money. You’re never getting value for those top of the line parts though.
Except that’s not it. The 7980X speed is 1/2.2 = 0.45 render/minute, which is 64% faster than the 7970X (1/3.6=0.28 render/minute). An faster way to do the math is 3.6/2.2 = 1.64 --> 64% faster. What Steve did is 2.2/3.6=0.61 --> 1-0.61=0.39 –> 39% faster.
It’s not the first time I see GN stumble on percentages when talking inverse performance metrics (think graphs where “lower is better”). Sometimes it doesn’t matter much because the percentage is small. Like with 1/0.90=1.11, 11%~10%. But on bigger margins it gets very inaccurate.
Another way to see this is by pushing the example to the extreme. Take the R7 2700 at the bottom of the chart completing the test in 26.9 minutes. Using the erroneous formula (2.2/26.9=0.08 --> 1-0.08=0.92) we get that the 7980x is 92% faster than the 2700, which is obviously silly, in reality it’s 12x faster.
4c/8t Comet Lake? So that’s also circa 2015 Skylake.