Core i7-7740X CPU by Intel Review

Intro

The Core i7-7740X is one of the new CPUs from Intel using socket LGA2066. With four cores, eight threads and maximum clock of 4.5 GHz, it is aimed on the top/mainstream segment. Check it out!
Recently, Intel launched a new high-end platform, the X299, that uses the new LGA2066 socket. The new CPUs for this platform are codenamed Kaby Lake-X and Skylake-X, and while the highest-end model is the Core i9-7900X (read its review here), which has 10 physical cores, 20 threads, 3.3 GHz base clock, and 4.5 GHz Turbo clock, the Core i7-7740X has only four cores, among other limitations.
The X299 platform comes to replace the previous HEDT (high-end desktop) platform, X99. The main feature of this platform is, besides the support for high-end CPUs, the memory access in four channels.
For this platform, Intel launched not only high-end CPUs, with six or more cores, but also two four-core CPUs, the Core i7-7740X (which we are reviewing today) and one Core i5. These two processors are based on the “Kaby Lake X” architecture, while the other ones are based on “Skylake-X” architecture. Besides having less cores, these two basic moldels have only 16 PCI Express 3.0 lanes, and access memory with only two channels.
The table below shows the CPUs launched (so far) for this new platform. Intel already annouced a few more models to be launched briefly.

Model	Base Clock	Turbo Boost Clock	Cores/Threads	L3 Cache	PCI Express lanes	TDP	Memory channels	MSRP
Core i9-7900X	3.3 GHz	4.3 GHz	10/20	13.75 MiB	44	140 W	4	USD 999
Core i7-7820X	3.6 GHz	4.3 GHz	8/16	11 MiB	28	140 W	4	USD 599
Core i7-7800X	3.5 GHz	4.0 GHz	6/12	8.25 MiB	28	140 W	4	USD 389
Core i7-7740X	4.3 GHz	4.5 GHz	4/8	8 MiB	16	112 W	2	USD 339
Core i5-7640X	4.0 GHz	4.2 GHz	4/4	8 MiB	16	112 W	2	USD 242

As you can see, the Core i7-7740X does not offer two of this platform highlights: the quad-channel memory access, and the high number of PCI Express lanes. Actually, its specs are very similar to the Core i7-7700K’s, except for 100 MHz more on the base clock and the official support to DDR4-2666 memories. Besides that, it is basically the same CPU packed on a new socket, even costing the same.
On some motherboards, there is not even support for a PCI Express 3.0 x16 slot when a Kaby Lake-X CPU is being used; even a single video card will work at x8 speed. Besides that, with these processors, you can only use half of the motherboard sockets, because the memory controlled embedded in the CPU supports only two channels, not four.
Figure 1 shows the Core i7-7740X CPU.

Figure 1: the Core i7-7740X

In Figure 2 we have the underside of the CPU.

Figure 2: underside of the Core i7-7740X

Figure 3 shows the Core i7-7740X at the side of the Core i9-7900X. Notice that they use the same socket, but have different heatspreaders.

Figure 3: the Core i7-7740X (left) and the Core i9-7900X (right)

For our benchmarks, we compared the Core i7-7740X to the the Ryzen 7 1700X (read review here), which is its direct competitor. We also included the Core i7-7700K (review), which is very similar to the reviewed CPU. We also included the Core i9-7900X (read the review) and the Core i7-6950X (review here), but please mind that those two last ones are not direct competitors to the Core i7-7740X, because they cost a lot more.
We used a GeForce GTX 1080 video card on all tests.
Let’s compare the main specs of the reviewed CPUs in the next page.