The marketing has been that Intel's E Core line (eg Sierra Forest) has more cores with more power efficiency, whereas the P Core line (eg Granite Rapids) has much higher per-core clock speed. This would make sense, but doesn't seem to be reflected in the actual numbers. Sierra Forest 6780E has 144 cores with 2.2 GHz Base Frequency at 330W TDP [0], whereas the top of the line Granite Rapids 6980P is expected to have 128 cores at only 2 GHz Base Frequency at 500W TDP [1].
From this, it seems like Granite Rapids is being rolled out later, with fewer cores, lower clock speeds, and more power. Am I missing something? Why would anyone go for Granite Rapids over Sierra Forest? (It does look like the L3 cache is bigger for the P Cores, perhaps that is the main selling point...)
[0] https://www.phoronix.com/review/intel-xeon-6780e-6766e [1] https://www.tomshardware.com/pc-components/cpus/5-new-intel-grante-rapids-chips-discovered-with-up-to-128-cores-500w-tdp