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Kaby Lake X i7-7740X overclockable to 5 Ghz on air

The i7-7740X is one of two quad-core processors on X299. Ivybridge-E was the last time we had a quad core on the enthusiast platform, and it wasn't designated as an 'X' SKU. (Source: NotebookCheck)
The i7-7740X is one of two quad-core processors on X299. Ivybridge-E was the last time we had a quad core on the enthusiast platform, and it wasn't designated as an 'X' SKU. (Source: NotebookCheck)
The i7-7740X has top of the line single core performance, but lags behind six and eight core processors in multi-threaded workloads. Anandtech have managed to push their CPU to 5.0 GHz stable on all cores. This could indicate better binning than the i7-7700K, but a quad core is still on odd choice on the enthusiast X-series platform.

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During our review of the new Kaby Lake X CPU, the i7-7740X (US$349), we found that it was barely the fastest CPU we had tested in single threaded workloads when running at stock speeds. However, it lagged behind 6C/12T and 8C/16T offerings from Ryzen (such as the R5 1600 at US$210) and Skylake-X during multi core benchmarks, due to only being a 4C/8T like the i7-7700K (US$308)

We also noted that the stock performance difference from the i7-7700K was somewhere between non-existent and tiny. The i7-7740X is essentially an i7-7700K with a 100 MHz higher base close, a 17 Watt higher TDP, and a US$40 higher price tag. You also must factor in a more expensive X299 motherboard at approximately US$100-120 more than a standard Z270 board.

Overclocking is where the difference between these CPUs starts to show. Anandtech has tested their i7-7740X overclocking performance using air cooling and managed to get it to be stable with all four cores running at 5.0 GHz. This is in comparison to multiple i7-7700K samples which they had running between 4.6-4.8 GHz stable. While this is a small sample set, it may show that the Kaby Lake X chips are at least better binned than the standard K-series.

Even with the i7-7740X running at 200-400 MHz higher than the i7-7700K, it might not justify the extra cost for the ecosystem. For those who don't need the features of X-series, they're probably better off saving some money. For those people who have a use for an X299 based system, they're likely to be better served by buying a proper enthusiast chip like the 6C/12T i7-7800X (US$416) — but not for gaming.

Note: All prices retrieved from Amazon at the time of writing

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> Notebook / Laptop Reviews and News > News > News Archive > Newsarchive 2017 07 > Kaby Lake X i7-7740X overclockable to 5 Ghz on air
Craig Ward, 2017-07-25 (Update: 2017-07-26)
Craig Ward
Craig Ward - News Editor
I grew up in a family surrounded by technology, starting with my father loading up games for me on a Commodore 64, and later on a 486. In the late 90's and early 00's I started learning how to tinker with Windows, while also playing around with Linux distributions, both of which gave me an interest for learning how to make software do what you want it to do, and modifying settings that aren't normally user accessible. After this I started building my own computers, and tearing laptops apart, which gave me an insight into hardware and how it works in a complete system. Now keeping up with the latest in hardware and software news is a passion of mine.