Cioby :
Well with the new ShadowPlay working well, I can stream while gaming at 4K Ultra to 1080p and I don't really have any issues with my old i7 4770k. It feels more like a fake marketing scheme on behalf of AMD that's trying to steal market shares from Intel on the gamer department. But that's just my case, I take really good care of my system so it works at 100% potential.
And with 4790k going up to 5Ghz speed, it will always run better in games, than a 16 core 3Ghz CPU that costs 3 times the original price. That's if his CPU can OC also, otherwise 4Ghz will be outdated soon.
never said it wouldn't run with the old one, but it'll run better with the more core, that's why intel had to release the coffelake as soon as possible, coz the extra cores does had it's own merits
u're right that faster CPU would always be better for gaming, but that's because most of the games right now rarely use above 4 core [which i think explains why intel just sat around happily with the 4 cores in the mainstream market for the last 7 generation....], intel also does had IPC, which explains why it can achieve higher fps in most games [if not all], but more cores does make the game more stable, allow better multitasking [like gaming and streaming and such]
he don't need to upgrade [never said he had to] anytime soon, his 4790k can still last another few years, but if he wanted to upgrade now, the performance difference is already showing up there...
PS:
even if it's only a fake marketing, AMD sure does fool a lot of reviewer and intel themselves there, since many people praise that Ryzen lineup, a lot of reviewers does give their thumbs up for this new CPU[albeit most of the time they praise it for better multitasking system rather than a full-gaming system], and intel had to release coffelake sooner in order to retake the market...