Those of you saying the 6700k and 7700k could match up with its performance simply by raising the clock speed. That argument is moot since the 8700k can be just as easily overclocked.
But it doesn't look like it can be overclocked any further than Kaby Lake can, as both can be OC'd at about the same rate to 5.0 or 5.1GHz.
Would be really nice if someone did some side-by-side testing where both the i7-7700K & i7-8700K were OC'd to the same frequency, so you could actually see if those extra cores actually did provide an actual +50% in performance...oh wait, someone (Toms' Hardware) already did:
http://www.tomshardware.com/reviews/intel-coffee-lake-i7-8700k-cpu,5252.html
When they did their testing (especially for the games), they not only tested both CPUs at stock speeds but also OC'd both systems to 4.9GHz. They also gave a supposedly glowing review of Coffee Lake...but I found the results very interesting, as those extra 2 cores provided:
-- only a 7.0% improvement in average FPS, & a 3.125%
drop in minimum FPS in Ashes of the Singularity: Escalation
-- only 3.1% improvement in average FPS, & only a 5.3% improvement in minimum FPS in Civilization VI (along with only a 1.5% reduction in AI turn time)
-- only 0.4% improvement in average FPS, but
no improvement in minimum FPS in Battlefield 1
-- only a 3.1% improvement in average FPS, but a surprising 23.4% improvement in minimum FPS, for Warhammer 40K: Dawn of War III
-- 13% improvement in average FPS, & 19.1% improvement in minimum FPS for GTA V
-- only a 2.1 improvement in average FPS, & a whopping
0.3% improvement in minimum FPS for Hitman (sorry, forgot the sarcasm tag there)
-- a 3.5%
drop in average FPS, & a 2.5%
drop in minimum FPS for Middle Earth: Shadow of Mordor
-- a mere 0.5% increase in average FPS, & a 3.8% increase in minimum FPS for Project CARS
-- a 0.9%
drop in average FPS, & a 1.1%
drop in minimum FPS for Far Cry Primal
-- a 0.4% increase in average FPS, & a 0.9% increase in minimum FPS for Rise of the Tomb Raider
If you're keeping track, that was 9 games tested where an OC'd i7-8700K faced off against an OC'd i7-7700K at the same clock speeds...& of those 9 tests, only 7 of the 9 showed Coffee Lake pulling ahead of Kaby Lake, & of those 7 only 2 showed improvements above 10% (& 1 of those only qualified in the minimum FPS department).
That tells me a couple of things:
1. Just as Intel advocates have been telling us for years now, PC games are still primarily optimized for 4-8 cores/threads. So the extra 2 cores/4 threads that Coffee Lake is bringing to the table don't really provide a whole lot of actual improvement in game performance.
2. If you have a Kaby Lake (or even a Skylake) system, you have
zero financial incentive to "upgrade" to Coffee Lake, especially if you can overclock your current system. Paying $500-600USD for a measly extra 3-5% in-game performance, when you most likely spent that much within the past year or so on the Skylake/Kaby Lake system, sounds like a real waste of your money. Especially since that's the kind of price that a good GPU upgrade provides you -- like, say, replacing a GTX 1060 with a GTX 1070 to go up to a 1080p/144Hz monitor (or to a 1440p/60-75Hz monitor), where you're going to see a consistent 25% or better improvement in performance...or especially if you can snag a GTX 1080 for that price & get even better performance out of the system.
3. For those that have bought Ryzen-based systems, or are considering the switch to a Ryzen system, it seems like the price comparisons are still about the same as they were before. The only difference is that, instead of comparing a Ryzen build against the "I'll buy it if money is no object" i7-7700K system, it's now going to be an i7-8700K "money is no object" system. Not because Ryzen has magically gained performance...but because Coffee Lake only offers a slight improvement in gaming performance for the same (or slightly higher) price than the prior Kaby Lake systems did.
