Intel Coffee Lake Conclusion

It has been a long time coming, but we finally have something bigger than a quad-core processor on Intel’s mainstream platform. Fundamentally it might be the same architecture as the processors preceded it, but after a decade of quad-core Intel parts, it comes as a welcome improvement. Intel sampled us the Core i7-8700K and the Core i5-8400 for this set of initial launch testing, with the goal of offering more high performance cores at more mainstream price points without having to invest in the company's more expensive and otherwise more complex HEDT platforms.


The Core i7-8700K

The Core i7-8700K in our testing was designed to be the new halo mainstream processor: many cores and the highest frequencies seen on an Intel part out of the box, with the option of overclocking thrown in. With a peak turbo frequency of 4.7 GHz, in benchmarks that could be stripped down to a single core with no other work going on, the i7-8700K took home the bacon.

The problem here is the same problem we’ve seen with big core parts and Windows 10, however: these large processors can only take so much before having to move threads around, to keep both the frequency high and the energy density low. All it takes is for a minor internal OS blip and single-threaded performance begins to diminish. Windows 10 famously kicks in a few unwanted instruction streams when you are not looking, and as a result the CPU fires up another CPU core and drops to a lower turbo bin. Consequently the average single thread performance seen on the 8700K might be equal or lower than that of the previous generation. It becomes an infuriating problem to debug as a reviewer.

Nonetheless, when software needs to take advantage of the cores, the Core i7-8700K will run through at an all-core turbo frequency of 4.3 GHz, consuming about 86W in the process. The jump up from a quad-core to a hex-core for only a $20 difference will be immediately noticeable in the software that can take advantage of it.

What is interesting to note is that the Core i7-8700K essentially kills the short-lived Kaby Lake-X parts on the X299 high-end desktop platform. Again, for a few extra dollars on the 8700K, a user can save over $100 on the motherboard, get more cores and more performance, and not have the hassle of dealing with a hybrid X299 platform. It does make me wonder why Intel released Kaby Lake-X in the first place, if they knew just how short lived they would be.

When comparing against the Core i7-7800X, a high-end desktop part at a similar price and with the same core count but a lower frequency, it really comes down to what the user needs. Performance easily favors the Core i7-8700K, however that cannot replace the quad-channel memory (up to 128GB) and the 28 PCIe lanes that the Core i7-7800X can support. In most circumstances, especially gaming, the Core i7-8700K will win out.

Intel’s 8th Generation CPUs: The Ones To Watch

Intel also sampled us the Core i5-8400, showing that six-core processors can cost less than $200. This processor, along with the Core i3-8100, will form the new backbone of general computing when using Intel components: the Core i3-8100 replaces old Core i5 processors for around $120, and enthusiasts who simply want a little more oomph can go with the Core i5-8400 at $190 at retail. It almost comes across as adding 50% cost for adding 50% performance. Personally I think the Core i3-8100, if made widely available, will be a top-selling processor for casual desktop users and gamers who were previously looking for a good performance-per-dollar part.

There is one other comparison to note: the Core i5-8600K and the Core i7-8700. These two parts are $50 apart, however the Core i7-8700 has double the threads, +10% raw frequency, 33% more L3 cache, and 1/3 lower TDP. The Core i5-8600K has overclocking, however going up to the i7 ensures stability, and should offer more raw performance. It will be interesting to get these two in to test, and especially to see if the TDP rating makes a significant performance difference.

Today’s Review Takeaway

We finally have six-core processors on Intel’s mainstream platform, which has driven up the core counts (and frequencies) of the company's low and mid-range processors. For anyone looking at building a system in the last 6-12 months, they should be able to build an equivalent with the latest-generation processor for $50-$100 less. Or spend the same and get a few more cores to play with. The last time we had this situation was a decade ago, and hopefully it won’t take another decade to happen again.

Dedicated reviews for the processors (with more gaming tests) are on the cards. Stay tuned!

CPU Gaming Performance: Grand Theft Auto


View All Comments

  • Koenig168 - Friday, October 6, 2017 - link

    Hmm ... rather disappointing that Anandtech did not include Ryzen 1600/X until called out by astute readers. Reply
  • mkaibear - Friday, October 6, 2017 - link

    ...apart from including all the data in their benchmark tool, which they make freely available, you mean? They put in the CPUs they felt that were most relevant. The readership disagreed, so they changed it from their benchmark database. That level of service is almost unheard of in the industry and all you can do is complain. Bravo. Reply
  • Koenig168 - Friday, October 6, 2017 - link

    Irrelevant. While I agree with most of what you said, that does not change the fact that Anandtech did not include Ryzen 1600/X until called out by astute readers. To make things a little clearer for you, the i7-8700 is a 6C/12T processor. The Ryzen 1600 is a 6C/12T processor. Therefore, a comparison with the Ryzen 1600 is relevant.

    You should have addressed the point I made. Instead all you can do is complain about my post. Bravo. (In case this goes over your head again, that last bit is added just to illustrate how pointless such comments are.)
  • mkaibear - Saturday, October 7, 2017 - link

    So your point is, in essence, "they didn't do what I wanted them to do so they're damned for all time".

    They put up the comparison they felt was relevant, then someone asked them to include something different - so they did it. They listened to their readers and made changes to an article to fix it.

    Should they have put the R5 in the original comparison? Possibly. I can see arguments either way but if pushed I'd have said they should have done - but since even the 1600X gets beaten by the 8400 in virtually every benchmark on their list (as per they would then have been accused by the lurking AMD fanboys of having picked comparisons to make AMD look bad (like on every other article where AMD gets beaten in performance).

    So what are you actually upset about? That they made an editorial decision you disagree with? You can't accuse them of hiding data since they make it publicly accessible. You can't accuse them of not listening to the readers because they made the change when asked to. Where's the issue here?
  • mkaibear - Saturday, October 7, 2017 - link

    OK on further reading it's not "virtually every" benchmark on the list, just more than half. It's 50% i5 win, 37% R5 win, 12% tied. So not exactly a resounding triumph for the Ryzen but not as bad as I made it out to be.

    In the UK the price differential is about £12 in favour of the i5, although the motherboard is about £30 more expensive (though of course Z370 is a lot more fully featured than B650) so I think pricing wise it's probably a wash - but if you want gaming performance on anything except Civ VI then you'd be better off getting the i5.

    ...oh and if you don't want gaming performance then you'll need to buy a discrete graphics card with the R5 which probably means the platform costs are skewed in favour of Intel a bit (£25 for a GF210, £32 for a R5 230...)
  • watzupken - Saturday, October 7, 2017 - link

    As mentioned when I first called out this omission, I would think comparing a 6 vs 4 core irrelevant. This is what AnandTech recommended to lookout for on page 4 "Core Wars": Core i5-8400 vs Ryzen 5 1500X.
    You be the judge if this makes sense when there is a far better competition/ comparison between the i5 8400 vs R5 1600. Only when you go reading around and you realized that hey, the i5 8400 seems to be losing in some areas to the 1600. I give AnandTech the benefit of the doubt, so I am done debating what is relevant or not.
  • KAlmquist - Friday, October 6, 2017 - link

    The Anandtech benchmark tool confirms what Ryan indicated in the introduction: the i7-8700k wins against the 1600X across the board, due faster clocks and better IPC. The comparison to the i5-8400 is more interesting. It either beats the 1600X by a hair, or loses rather badly. I think the issue is the lack of hyperthreading on the i5-8400 makes the 1600X the better all-around performer. But if you mostly run software that can't take advantage of more than 6 threads, then the i5-8400 looks very good.

    Personally, I wouldn't buy i5-8400 just because of the socket issue. Coffee Lake is basically just a port of Skylake to a new process, but Intel still came out with a new socket for it. Since I don't want to dump my motherboard in a landfill every time I upgrade my CPU, Intel needs a significantly superior processor (like they had when they were competing against AMD's bulldozer derivatives) to convince me to buy from them.
  • GreenMeters - Friday, October 6, 2017 - link

    So Intel still isn't getting their head out of their rear and offering the option of a CPU that trades all the integrated GPU space for additional cores? Moronic. Reply
  • mkaibear - Friday, October 6, 2017 - link

    Integrated graphics make up more than 70% of the desktop market. It's even greater than that for laptops. Why would they sacrifice their huge share of that 70% in order to gain a small share of the 30%? *that* would be moronic.

    In the meantime you can know that if you buy a desktop CPU from Intel it will have an integrated GPU which works even with no discrete graphics card, and if you need one without the integrated graphics you can go HEDT.

    Besides, the limit for Intel isn't remotely "additional space", they've got more than enough space for 8/10/12 CPU cores - it's thermal. Having an integrated GPU which is unused doesn't affect that at all - or arguably it gives more of a thermal sink but I suspect in truth that's a wash.
  • Zingam - Saturday, October 7, 2017 - link

    We need a completely new PC architecture - you need more CPU cores - add more CPU cores, you need more GPU cores add more GPU cores, all of them connected via some sort of Infinity fabric like bus and sharing a single RAM. That should be possible to implement. Instead of innovating Intel is stuck in the current 80s architecture introduced by IBM. Reply

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