When Intel released their 8th Generation Core “Coffee Lake” processors the biggest complaint was that users had to buy a brand new 300-series chipset as these chips were said to be incompatible with older 200-series and 100-series motherboards, despite having an identical LGA1151 socket. There were debates whether Intel was doing this to ensure people buy motherboards every two generations or these chips indeed had special electrical requirements the come with the increased core counts. Intel did not really explain why quad-core chips like the i3-8100 and the i3-8350K couldn’t work on the older motherboards as they did not have increased core counts.
Well it turns out that “Coffee Lake” is pin-compatible with older LGA1151 motherboards based on the 200-series and 100-series chipsets. Modders were able to get these chips to work on older platforms. Intel uses software to block these chips from working on older motherboards, this comes in the form of the CPU’s microcode, the iGPU’s UEFI GOP driver, and certain management engine bootstraps on the side of the motherboard BIOS that lets it recognize new chips.
Overclock.net users rootuser123, LittleHill, dsanke, elisw, Mov AX, and 0xDEAD were not only able to get these chips to work on the older motherboards, but also found ways to iron out several stability and compatibility issues. You can check out the guide here.