Intel's new W-1300 series of Xeon processors briefly emerged in a compatibility list showing all CPUs supported in Intel's latest LGA1200 socket. However, a few hours later they were taken down. This could mean that these new Xeon processors will support the same socket as Intel's consumer-grade Rocket Lake products.
Because these chips are compatible with the LGA 1200 socket, they should be nearly identical to Intel's upcoming Core i5, i7, and i9 Rocket Lake parts, but have a few alterations that include and support for vPro technologies and ECC memory.
Intel has been doing this for years with its lower-end Xeon processors, re-purposing lower-end Core i5, i7, and i9 parts and turning them into Xeon chips. The strategy makes a lot of sense, as not all servers and workstations require HEDT levels of processing power and connectivity.
However, since the Skylake generation, Intel has severely limited its entry-level Xeons' motherboard compatibility and requires them to run in a workstation/server "designed" chipset. So yes, while these chips have the same socket compatibility as Intel's consumer desktop chips, Intel's W-1300 Xeons will not work in a standard H-, B-, or Z-series motherboard.
The W-1300 CPUs, which appeared on an ASRock list, were the W-1390, W-1390T, W-1350P, W-1350, and W-1370.
The main differences we can find between each Xeon chip are its TDP and with some, its amount of L3 cache. For instance, chips like the W-1350, W-1390, and W1-1370 have an average TDP of 80W. The 1390T, has the lowest TDP at just 35W, and the W-1350P has the highest TDP of 125W.
Additionally, the W-1350 & W-1350P are equipped with less L3 cache, coming in at 12MB instead of 16MB. Presumably, this reduction in L3 cache is due to a lower core count compared to its other siblings.
Unfortunately, that's all we know (if it's even accurate), for now. We still don't know what prices will be, what core counts these chips will have, and what boost frequencies these chips will be equipped with. (But expect a maximum of 8 cores for W1300 chips due to the Rocket Lake architecture.)
Hopefully, we should have more information on Intel's new W-1300 chips right around or after the official Rocket Lake launch.