The positioning of Intel's Kaby Lake-X chips has been a bit cloudy since their introduction back at Computex last year. The four-core, four-thread Core i5-7640X and four-core, eight-thread Core i7-7740X offered minor clock speed bumps compared to their then-contemporary Kaby Lake mainstream desktop brethren, but required buyers to give up IGPs and pony up for pricier X299 boards those chips couldn't fully light up. That formula evidently didn't find enough takers, especially after the October 2017 introduction of the blue silicon giant's Coffee Lake processors. A new item in Intel's document management system specifies the discontinuation of the Intel Core i5-7640X and Core i7-7740X in their tray and retail boxed forms.
In the document, Intel admits that "market demand for [the Core i5-7640X and Core i7-7740X has] shifted to other Intel products." The company doesn't spell out the models to which the demand has shifted, but we imagine it is to eighth-generation mainstream desktop chips like the impressive six-core, 12-thread Core i7-8700K.
As we noted, last October's introduction of eighth-generation Core mainstream desktop chips appears to have been the final nail in the coffin for the HEDT-platform-riding Kaby Lake-X models. The Kaby-X chips didn't have the four memory channels or the expanded stable of PCIe lanes that the Skylake-X chips could bring to bear on pricey X299 motherboards. The Core i7-8700K sells for a similar price to the Core i7-7740X while offering higher base and turbo clocks, more cores, a functioning IGP, and compatibility with a wide array of more affordable motherboards.
Buyers with a Kaby Lake-X itch to scratch can still find the Core i5-7640X and Core i7-7740X for sale at places like Amazon, but the days for these processors are definitely numbered. Hat tip to David Schor for spotting the change.