Intel's desktop Kaby Lake CPUs haven't even been officially announced yet, but the folks at Tom's Hardware got their hands on a sample of the blue team's biggest, baddest next-gen chip for the desktop so far—the Core i7-7700K—ahead of its launch. The site did what any of us would do in that enviable situation: test the chip's performance in both stock-clocked and overclocked configurations.
The basic specs of the Core i7-7700K that Tom's reports are about in line with the rumors and leaks we've seen so far. Tom's says the chip has a 4.2 GHz base clock and a 4.5 GHz Turbo speed, and its four cores and eight threads slip into a 95W TDP—up slightly from the Core i7-6700K's 91W figure. That TDP increase is borne out by a small increase in power consumption in the site's testing—141W under a stock-clocked Prime95 Small FFTs load for the Kaby Lake chip, up from 133W for the Core i7-6700K running the same torture test.
We won't spoil the site's detailed performance numbers, but on average, the stock-clocked i7-7700K pulled out a 3.6% performance improvement over the i7-6700K. Given its increased power draw, Tom's says that makes the Kaby Lake chip less efficient than its Skylake counterpart.
Of course, stock-clocked performance is one thing, but many folks eyeing the i7-7700K are doubtless wondering how Intel's improved 14-nm process technology translates into overclocking headroom. Every chip's overclocking performance will be different, of course, thanks to the silicon lottery. Where our Skylake chips generally have no issue hitting 4.6 GHz and sometimes 4.7 GHz, Tom's was able to take its i7-7700K to 4.78 GHz with 1.3V running through the core.
At those settings, the chip reached a dizzying 82° C above ambient (a chilly 15° C or 59° F, in these tests), compared to 60° C over ambient for the site's Core i7-6700K running at 4.6 GHz. Whatever a given i7-7700K's overclocking performance, it appears builders will still need to keep heavy-duty coolers on hand to realize maximum performance from their chips.
We still don't have any official word about Kaby Lake on the desktop, so it remains to be seen whether the performance, efficiency, and thermal behavior that Tom's observed with its i7-7700K sample are reflective of retail chips. Still, the numbers are intriguing. We'll hopefully learn more about Intel's next generation of desktop processors—and get our own idea of its performance—soon.