It looks like you're new here. If you want to get involved, click one of these buttons!
Has there ever been a quieter launch of a new, top of the line gaming CPU?
The short version is, it's better than Haswell, though not by very much. That is, at least, an improvement over Broadwell, which was worse than Haswell. Clock speeds on the Core i5-6600K are the same as for the Core i5-4690K, while the base clock speed on the Core i7-6700K is the same as the Core i7-4790K. Max turbo on the 6700K is down to 4.2 GHz, from 4.4 GHz on the 4790K. Sky Lake does tend to be several percent faster at the same clock speed than Haswell. Rumors have it that with overclocking, Sky Lake can clock a little higher than Haswell.
But while reviews came out on Wednesday, retail availability isn't there yet. New Egg says the parts are launching next Friday. So Wednesday was basically a paper launch, and it's not clear how soon there will be heavy volume at retail. Wednesday only officially launched the overclockable K-series parts, while the rest of the Sky Lake lineup is coming a little later this month or next. Also notable is that the K-series parts don't come with a stock cooler at all. Not that using Intel's awful stock coolers was ever a sensible thing to do if you wanted to overclock.
Interestingly, Sky Lake's official TDP goes up from Haswell and even Devil's Canyon, in spite of the shrink from 22 nm to 14 nm. Then again, the claimed 88 W TDP of a Core i7-4790K always was pretty much a lie to begin with. So Sky Lake's 91 W is probably just a return to honest labeling.
Sky Lake uses a new socket, LGA 1151, and can use either DDR3 or DDR4 memory. All of the motherboards available so far use DDR4, but DDR3 is presumably coming. With the price difference between DDR3 and DDR4 shrinking, if you're willing to shell out for Sky Lake, I'd go with DDR4 unless you've got a bunch of DDR3 that you're itching to re-use.
Is Sky Lake a reason to upgrade from an overclocked Sandy Bridge system from 2011? Unlike some media reviews, I'd say no. If you've got an AMD system or a pre-Sandy Bridge system, I'd see Sky Lake as pretty strong evidence that there aren't any huge gaming CPU upgrades just over the horizon, so it's fine to upgrade whenever you're ready and feel the need to. The x86 CPU architecture is very mature and Intel is having a lot of trouble squeezing further per-core improvements out of it.
With Sandy Bridge now out for so long and Intel having trouble improving much ever since, AMD has presumably had plenty of time to figure out how Intel made Sandy Bridge so good and do likewise with Zen next year. So it's likely that with Zen cores, AMD will have something a lot more competitive with Intel than what AMD has to offer today. That sort of competition is good for consumers, of course. And, of course, if Zen is another disaster to follow Bulldozer, then AMD will likely go bankrupt--and will certainly deserve to.