From the looks of it Comet Lake-S and Rocket-Lake-S will be the only two generations processors that will work on the LGA1200 series motherboards, at least that's how it seems right now. That means you will not be able to upgrade fast based on your motherboard.
Next year in 2021 Alder Lake has been scheduled, it's mentioned that the pin count once again will change, towards a socket LGA1700. So while LGA1200 has just been introduced it will only last two generations, making a motherboard not a rather no so ling long-term investment.
It is Lit-Tech, a Taiwanese-based manufacturer responsible for Voltage Regulator Testing Tools in the Asian market listing Alder Lake-S compatible equipment already. It's not the first time we hear of this, back in January a leak of the Momomo_US and Komachi_Ensaka accounts told that the successor of the LGA 1200 socket would be LGA 1700, and that would be ... the Alder Lake-S platform, which in addition to a new socket will bring a new rectangular format for the processors, which were normally square at least on the Intel side. It is also rumored that "Alder Lake-S" would follow a BIG-little style of processor cores, massive cores for hefty workloads and small ones to remain energy friendly.
Taiwanese website PC_Shopping then mentioned a rumor that Intel also would combine different CPU cores with Alder Lake-S in the desktop. Eight "small" and eight "large" cores would be merged together, add to that a graphics unit, all in one package. According to the leaked slide, a CPU with 8+8 big.little cores would have a TDP of 125 watts. The socket design would be LGA 1700. The process technology would be based on Foveros technology, where Intel is stacking die's onto one package (think HBM2 on a GPU).
Alder Lake-S processors would have dimensions of 45×37.5mm, while current processors such as the i9-9900K have dimensions of 42.5 × 42.5mm. This rectangular design and the rather massive number of pins are most likely due to a design change towards a multi-die design housing.
LGA Socket 1700 for Alder Lake-S in 2021? (8 BIG + 8 little cores)
