TigerLake client uses Willow Cove cores. I would expect IceLake Xeon to use the Sunny Cove cores (same as IceLake client) and TigerLake Xeon to use Willow Cove, but I haven't seen evidence that is the case.

Well, other than precedent. We have never seen Intel suddenly surprise the market by using a different core type in a chip family's Xeon SKUs than was used in the mobile and desktop SKUs. And part of that (I conjecture, having been in the rodeo with them since 486 days) is that they like to use the consumer versions of the chips to suss out errata to be fixed before the Xeons are taped out and released. It is true that some features do differ, such as support for ECC RAM and perhaps activation of TSX or extra FMA unit, but these are really just variations on the same core family.

Given how late Ice Lake Xeons are, Tiger Lake Xeons are irrelevant.

Or more likely the 10nm process yield issues are the reason Ice Lake Xeon's are late. One potential is that Ice Lake Xeons are less relevant because it is on market short period before replaced by Sapphire Rapids. Since they got the Tiger Lake Xeons running in lab in June, and it should take them about year to get it to servers. And I doubt that they would have manufacturing issues with Tiger Lake Xeons when they can manufacture Ice Lake Xeons. As for Intel being irrelevant in servers, I doubt that they would go from over 90% market share with on paper inferior products to irrelevant in a year.

That is MUCH better it seems? Because then you don't randomly throw away lots of performance because some 512 items hit so there is less risk in using 512.

I wonder how many clock cycles that'd take ;-)

They made it sound like some instructions were more power hungry than others. The impression I got is that the unit can run some kinds of streams without reduction Of clock.