Difference between K chips and non K?

[Kevinkevs]

People say the only difference is that the K can be overclocked and that is the only difference. However when I search up the i5 6600k vs i5 6600 the non k version has a base of 3.3ghz while the k has 3.5ghz.. So does the K have better performance even when not overclocked?

 

[atomicWAR]

yes the K chips do have more performance when not overclocked due to the 200mhz speed bump.

 

[Rexper]

The K chip is unlocked so it is able to overclock as long as the motherboard is also unlocked.
Stock and Max Turbo Frequencies can differ, normally the 'k's will be slightly higher. Stock doesn't matter unless you decide to turn of turbo boosting. Since both boost to the same frequency, their performance is equal.
The non k intel chips (as long as they don't include "OEM/Tray' in the name) includes a stock cooler, whereas the 'k' chips do not.

 

[synphul]

It can differ depending on the cpu. As atomicWAR pointed out there is a slight speed difference. Everything else is the same, cache etc. The k series is unlocked so can have the multiplier adjusted in the bios (provided the motherboard is capable like a z series board). K series for 6th and 7th gen cpu's no longer have coolers.

On past k series cpu's they did come with a stock cooler. Also on past k series like the i5's, the k vs non k was literally about the unlocked multiplier. They had the same base and turbo speeds out of the box. The 6th gen 6600 vs 6600k differ in base clock speeds. 7th gen i5 7600 vs 7600k there is a slight difference, the max turbo boost of the 7600k is 100mhz faster vs the 7600.

Not that those relate to the 6600 vs 6600k, just clarifying that there's no blanket 'k vs non k' feature that applies to all. It really depends when comparing specific models. K series didn't always mean without a stock cooler, it doesn't always mean a clock speed variation. If you don't plan to overclock there's not much reason to go with a 6600k. Not unless you're hoping it makes it slightly more appealing down the road if/when you decide to sell it off. Some buyers don't want cpu's that have been oc'd, others won't bother with a second hand or older cpu unless they can squeeze some extra performance out of it.