Intel Core i7-7740X CPU Review




The Intel Core i7-7740X is possibly one of the most misunderstood product launches in recent PC history. I’ve never seen a launch receive such negative press, but there has to be something that comes up once in a while. So, before I go into too much detail on the CPU, let’s see what we are dealing with and find out why it did or didn’t receive such a bad reaction from both the media and public alike. Does the i7-7740X have a place in the market, or is Intel shooting into the stars and hoping people will lap up their new platform with a seemingly under-specced processor that comes in at £350/$350-ish? Before I go any further, we are well aware that this is an extremely late review and that you have most likely read plenty of others, but here’s our take on it a few months down the line.

It wouldn’t be an Intel release without Intel releasing an entirely new platform with a few more pins to ensure that none of their new or old chips are cross-platform compatible. With this CPU, a new socket was born and it is in the shape of an LGA2066 package. For those astute among you, that is actually five less than the previous “2011” socket which was improved upon by various vendors to offer you an ‘OC socket,’ which actually had 2071 pins overall. It offered better voltage control as well as the ability to fine tune more voltages from within the UEFI.

There are a few massive drawbacks to the i7-7740X and they are some which I frankly find unforgiving. Perhaps Intel are trying to adopt an AMD-esque upgrade scheme with what they’ve done here, but I don’t see it being likely. As we know, AMD keep the same socket for many years, and allow their newer stuff to be used on the same platform. Intel, however, change platform every other release, so this model will not work unless they stick with the same package.

Intel have chosen to go down a very strange road with this chip release, and it has left a lot of people wondering just what on earth it is doing on a HEDT platform. To start off with, it only has 16 PCI-E 3.0 lanes, something that will leave you with a hampered system right out of the box as soon as you want to install an M.2 drive (if your board even allows it with these CPUs). Secondly, the memory controller only supports dual channel, rendering half of your eight (or four depending on the board) memory slots useless. The next big thing is that it only has four cores and eight threads … on a HEDT system. No, Intel, that’s just not right. Lastly, it also has a 21w increase in TDP (Thermal Design Power) which seemingly only adds an extra 100 MHz to the base clock over the i7-7700K on Z170/LGA1151, and it also removes the iGPU entirely from the substrate which should only bring power usage down.

Since we waited for a long time to publish this review, we have also been alerted to the fact that certain vendors are apparently releasing Kaby-X specific motherboards, whereby they only have four DIMMs, for example. Yes, that’s right. a HEDT with half of the supposed features removed, and being Kaby-X specific. Now there’s the normal Kabylake and Kaby-X on two entirely different platforms. Can you make sense of it?

Anyway, let’s carry on and check out the specs before rambling on too much.


Intel Sky&Kaby-X CPU Comparison

Testing platform

CPU: Intel Core i7-7740X Kaby-X
Motherboard: ASUS ROG STRIX X299-E Gaming
RAM: Crucial Ballistix Elite 16GB 3000 MHz
Storage: Crucial MX300 525GB
OS: Windows 10 Pro 64bit



Cinebench R15

PCMark 8

Ashes of The Singularity

Tom Clancy’s: The Division


I’m going to start off by saying that there are a lot of drawbacks with the i7-7740X, and only one or two positives that I can think of immediately. The first major issue that I can see, by looking at the above illustration, is the fact that the i7-7740X only comes with 16 PCI-E lanes. Meanwhile, the i7-7700K (on the Z270/LGA1151 platform) also only comes with 16 PCI-E 3.0 lanes. There was scope for improvement here, given that it is a HEDT platform, but Intel quite literally took a 7700K and slapped it on to an LGA2066 package. However, looking at the specs more closely, you will notice that the chipset (PCH) provides up to 24 PCI-E 3.0 lanes, which would provide you with a total of 40 lanes. Regardless of this fact, however, is that you will still only be able to use one GPU at full speed or dual GPUs at x8/x8 bandwidth. We know that this only gives you a small performance loss, but it is not something that should occur with a high-end system. Many places are saying that Intel is purposefully gimping their CPUs with the lack of PCI-E lanes in order to force people to buy the next model up. Is it true? I’ll leave that one for you to decide.

The next drawback is the increased TDP (Thermal Design Power) over the 7700K. Sure, it does run a little faster, but an increase to 112w over the previous 91w is a little excessive for something that is only 100 MHz faster. It also lost the iGPU entirely. Power draw isn’t exactly a big deal considering what the bigger chips manage to pull, but there’s no doubt that this one should be pulling less than the 7700K which still has an iGPU next to the CPU cores.

The biggest gripe that I have with this CPU is the fact that it only has a dual channel memory controller, rendering half of your memory slots entirely useless, and costing you the bandwidth that quad channel has to offer.

Given that the CPU itself costs around £350/$350, it is a tough pill to swallow considering that there are many other options out there for this price point. You also have to factor in a motherboard and memory, which aren’t cheap either. The motherboards, at their cheapest end of the spectrum, are north of £199/$200, which is something that we’ve started to become used to with the HEDT boards. Understandable, yes, as they have a lot of features. However, with the i7-7740X in them, they are rendered useless and therefore don’t actually serve any value to you as a consumer until you upgrade to something from the Skylake-X lineup of i7/i9 processors.

I’m not going to be handing out any awards for the Kaby-X CPUs as I do not deem them worthy. Gavin felt the same way. My personal feeling is that this is still just a chip that should never have been brought to life. It serves nearly no purpose to anyone wanting to actually make use of HEDT systems, and the chances are that by the time you want to upgrade, Intel will have moved on to another new socket/chipset making your board/CPU change more difficult in the long run. Sorry, Intel, but you really have left me feeling rather speechless here.

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