[Throwawayhahzoh]

You also need to look at cache real estate. Granite Rapids has 16KB more L1 data cache per core, and the instruction cache is a large 16 way, I could not find that for the Sierra Forest L1 I cache.

4 Sierra Forest cores form a cluster that shares 4MB of L2 cache, each Granite Rapids core has its own 2MB L2 cache.

Sierra Forest has 3MB L3 cache per cluster, for a total of 108MB for the 144 core parts which is a smaller total than the L2 caches. No firm word on L3 shared caches for Granite Rapids, but its predecessor Emerald Rapids has 5MB per core. At that level, the 6980P would have a total of 640MB, but rumor at the beginning of the year is saying "up to 480MB."

So much more space is being dedicated to Granite Rapids caches, and the end of Dennard scaling a couple of decades ago means they'll draw plenty of power at rest. As theandrewbailey says, you really have to benchmark what you plan to run on these CPUs, but many loads will benefit from the bigger cache hierarchy even if some of these bigger ones are slower as they tend to be.