The Guru of 3D published a review on the ASUS ROG STRIX X299-E Gaming
A quote from the article:
We review the ?349,- enthusiast class X299-E Gaming motherboard, yes the ASUS ROG STRIX. A nice looking motherboard in dark theme offering nice features, design and of course performance. This X299 motherboard can house Kaby-Lake-X and Skylake-X processors.ASUS ROG STRIX X299-E Gaming Review @ Guru3D
This motherboard is intended for Intel Skylake-X processors that will be released this summer based on Socket LGA2066, however, the motherboard also supports Kaby Lake-X procs in the form of the quad-core Core i7 7740K and Core i5 7640K. We got our grubby little paws on a 10-core Skylake-X processor, as such welcome to this full review (but not thanks to Intel). Intel's primary processor business has been releasing and refreshing quad-core processors for years now with an E type (e.g. Broadwell-E / Haswell-E) processor release every now and then. They had no rush and have been competitive and relaxed all the way for years now. Intel did anticipate Zen or Ryzen, but the AMD consumer-aimed Threadripper 16-core and Naples server segment 32-core made Intel step up its game a notch. Initially it was expected that Intel would announce a new 10 and maybe 12-core processor based on Skylake-X architecture. With everything that has been going on, there now have been a number of announcements going from top to bottom with an unexpected quad-core Kaby Lake-X release as well as announcements that entails Intel will release 18-core processors. The Skylake-X processors up-to 10 cores are going to be released initially. You will not see any availability for the 18, 16 and 14-core parts anytime sooner than October/November 2017. Skylake-X will release up-to 10-cores only. It is rumored that in August we'll see the 12-core part - but consider that intel isn't talking with EU press anymore, who really knows right?