Even worse: IPC data is pretty much useless when it comes to comparing CPU performance! How is it going to account for something like the introduction of AVX51

Even worse: IPC data is pretty much useless when it comes to comparing CPU performance! How is it going to account for something like the introduction of AVX512, doubling the data throughput per instruction? What about increased cache greatly reducing the number of instructions waiting for memory access, or a faster memory controller? How would you even begin to quantify a new PCIe generation doubling SSD bandwidth, or a better core interconnect reducing NUMA penalties? IPC is basically just a marketing number with today's CPUs. If you want to get a proper comparison, use a real-world benchmark.