Niggles: what is 8th gen though?
AB2012: The "Generations" regarding Intel CPU's relate to when the
Core Architecture started. The first generation were oddly numbered, but from the 2nd generation onwards, the first number of the model number generally relates to the Generation,eg, your i5-2500 is 2nd gen "Sandy Bridge", an i5-6600 is 6th gen "Skylake", i3-8100 is 8th gen "Coffee Lake", etc. Unlike the 90s where there were a lot of x86 instruction extensions added like MMX, SSE, the past decade has been very stable for the instruction set. Hardly any games use AVX (which even your CPU supports) and really there's nothing that actually "requires" a specific generation of new CPU to be used to avoid a crash (ie, no reason why an i5-2500 can't technically run most new games that "require" an i5-6600 / i3-10100, etc, even if they do run them a little slower).
Before the "1st generation" (Core i3/i5/i7); there were two more: Core & Core 2. e.g. Yonah and Merom
Before my current i7-6700, I had a Core2Duo E8400 (Quads were relatively expensive back then).