Each time Intel launches with every new release a new chipset which in my view actually could have been used by the 4 previous releases as well.
So fact is Intel does do the Intel on every generation and forces to buy a new set even if you do not need it at all.
These new releases are acutally not needing a new socket at all but guess what they simply play with the pins again by that AGAIN force you to buy a new motherboard as well.
So again there is absolute no need for a new design motherboard at all for the last 4 released generations but ofcourse that is not intels law.
The law says every new release must also sell a new chipset and preferred also alot of other chips to make even more profit.
Even though there is actually almost nothing changed besides a small processor speed update.
There are things to be said and opinions to be had about how Intel deals with motherboards and chipsets but ignoring the facts is not a good way to go at it.
Intel changes socket every 2 generations and that is usually 2 years:
2011 - s1155 - Sandy Bridge/Ivy Bridge
2013 - s1150 - Haswell/Broadwell
2015 - s1151 - Skylake/Kaby Lake
2017 - s1151v2 - Coffee Lake/Coffee Lake Refresh
2020 - s1200 - Comet Lake/Rocket Lake
There are changes in Haswell's s1150 (primarily FIVR) that would make socket not very compatible with SandyBridge/IvyBridge's s1155. This was reversed for Skylake with a similar effect.
This has advantages from both Intel and motherboard manufacturers perspective. Everyone knows what to expect. Intel keeps the two CPU generations close enough that issues from socket mid-lifetime release are smaller (not without problems if you remember PCIe 2.0 > PCIe 3.0 for example). Manufacturers know they need to rebuild BIOS halfway through board lifetime and that the socket has a defined lifetime. All of this is very convenient for all the involved parties as they know exactly what to expect. And this includes users.
The usual situation broke down in 2017 and continues to be broken because Intel does not have new CPUs. They have new generation with more cores and more recently also vulnerability fixes, but the new generation has been waiting for 10nm ever since. This makes it true that technically s1151 and s1151v2 could support the same CPUs and probably s1200 as well. If I were a motherboard manufacturer though, I would be very careful with wanting to do that - because of power requirements mostly. Skylake and Kaby Lake were fine with TDPs, anything after that and power consumption blew up in the high end (which is what you need to keep in mind when releasing a motherboard). s1200 boards make it very obvious with quite powerful VRMs on all boards so far.
One of Intel's faults there is perception - keeping the s1151 as socket. They could have done s1152 and the outcry would have been much smaller. Yes, enthusiast crowd would still scream at them but all the problems with choosing the compatible CPU/motherboard combination in all the forums and questions etc would not be common as they are now.
That 4 generations (or maybe 6) could be on one socket/platform is pretty unique and only because the architecture used in the CPU generations is almost exactly the same.
Does anyone really believe Intel does it to sell chipsets? This sounds pretty bullshit argument. They make far more profit on any CPU than a chipset.
Now, supporting an old platform over a long time has downsides.
- Cost. You are building BIOSes for chipsets that are old. For each of them you are building the BIOS for a larger number of CPUs. This adds complexity and testing must be hell.
- You need to keep the compatibility in mind. You cannot make technical changes that would break the platform in any way. You cannot improve some things because you need to keep everything working.
- No doubt motherboard makers are not very happy. On one hand, they cannot sell new motherboards. On the other, they need to support old motherboards much longer. Both add cost to manufacturer.
Even if you do this and keep a platform for long, some things will end up slightly broken at one point. There will be compatibility breaks somewhere in the middle of platform lifetime. Think about how older platforms addressed these issues, for example AM2/AM2+, AM3/AM3+, LGA775 or Socket 370.
