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Final Analysis
Superficially, Intel’s idea to transplant Kaby Lake onto its high-end desktop platform seems like it'd make sense. But ultimately, X299's excessive cost hamstrings Kaby Lake-X. In many ways, the Core i7-7740X reminds us of Intel’s Core i3-7350K. It's a great chip forced into a platform that doesn't match up with its price point.
Core i7-7740X is nearly identical to the existing -7700K; even its price is similar. At stock settings, the -7740X performs a lot like its mainstream counterpart, despite slightly higher base and Turbo Boost frequencies. We noticed the same performance characteristics as -7700K in lightly threaded workloads, such as gaming and most common desktop apps. But the -7740X pales in comparison to the brawnier Skylake-X models in heavy application tests. Lower idle power consumption numbers are likely a result of the -7740X's disabled graphics engine. However, the overall power and thermal measurements come out to be almost the same. Though we still don’t approve of the thermal paste Intel uses between its die and heat spreader, at least closed-loop liquid coolers are fine for this 112W chip.
The “X” in Kaby Lake-X promises extreme overclocking action, and we did eke out a few hundred megahertz over Core i7-7700K. That extra headroom is nice, but it doesn't translate to large gains in our gaming suite. In fact, at stock settings, the -7700K achieved higher average frame rates, while overclocking gave the -7740X a 1.19% advantage. The 99th percentile variances between the chips both fell under 1%, with the advantage going to Core i7-7700K in stock and overclocked configurations. In either case, the difference between these two CPUs is imperceptible, even after overclocking them both. Perhaps that'll improve as X299-based motherboards receive more fine-tuned firmware.
Intel's Core i7-7700K is one of the fastest gaming processors we've ever tested, so matching it is a good thing. But the -7740X doesn't make sense as an equal when we factor in the X299 platform. You are going to pay an extra ~$150 for an X299 motherboard compared to a more mature Z270-based setup, and gain exactly zero features. In fact, you lose the integrated GPU that could be useful for other tasks, such as Ultra HD Blu-ray playback. Dropping the -7740X into LGA 2066 actually disables motherboard features you're paying for like extra DIMM slots, Skylake-X's more robust power delivery, and hamstrung chipset functionality.
Our motherboard contacts have expressed a general reluctance to create Kaby Lake-X-specific motherboards, and unless that changes, there is little reason to jump up to the X299 with a Kaby Lake-X chip. Certain enthusiasts will pursue a stouter overclock from the Kaby Lake architecture, and -7740X delivers in that regard. Intel's pitch is that Core i7-7740X serves as an entry point to X299 that paves the way for upgrades to Skylake-X later. We don't believe there's a big market for an expensive path like that, though. For those with the upgrade itch, either stay with the Z270 and spend bigger on a high-end GPU, or splurge on a true HEDT-class processor.
Intel has its Coffee Lake CPUs coming to market later this year, and we've heard rumors of a six-core model landing on the mainstream desktop. Consider waiting for more information on that prior to going the X299/Kaby Lake-X route, if you're still interested in Core i7-7740X. Also, AMD's Ryzen Threadripper is coming soon. There are just so many reasons not to buy this thing...
Core i7-7740X doesn’t give you anything new. Yes, it's one of the fastest gaming chips ever made, but you can get similar performance from the mature Z270 platform for significantly less money. We appreciate the higher overclocking ceiling, but that doesn't translate into enough benefit to justify the extra investment.
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