Socket, Silicon and Security

The new CPUs have the LGA1200 socket, which means that current 300-series motherboards are not sufficient, and users will require new LGA1200 motherboards. This is despite the socket being the same size. Also as part of the launch, Intel provided us with a die shot:

It looks very much like an elongated Comet Lake chip, which it is. Intel have added two cores and extended the communication ring between the cores. This should have a negligible effect on core-to-core latency which will likely not be noticed by end-users. The die size for this chip should be in the region of ~200 mm2, based on previous extensions of the standard quad core die:

  • CFL 4C die: 126.0 mm2
  • CFL 6C die: 149.6 mm2
  • CFL 8C die: 174.0 mm2
  • CML 10C die: ~198.4 mm2

Original 7700K/8700K die shots from Videocardz

The only silicon we know to be guaranteed inside each retail box is that the ten core parts have to have the 10C silicon. Beyond that, Intel could make any of the eight core Core i7 parts use either a native 8C silicon, or 10C silicon with two disabled cores. Similarly, the six core Core i5 could either be native 6C silicon, harvested 8C silicon, or harvested 10C silicon. We have reached out to Intel for clarification, given that in previous generations Intel sometimes offered different TDP values for the harvested dies. There's even a possibility that Intel could be reusing the same Coffee Lake silicon masks and just binning them to Comet Lake specifications.

For security, Intel is applying the same modifications it had made to Coffee Lake, matching up with the Cascade Lake and Whiskey Lake designs.

Spectre and Meltdown on Intel
AnandTech Comet
Cascade Lake Whiskey
Spectre Variant 1 Bounds Check Bypass OS/VMM OS/VMM OS/VMM OS/VMM
Spectre Variant 2 Branch Target Injection Firmware + OS Firmware + OS Hardware + OS Firmware + OS
Meltdown Variant 3 Rogue Data Cache Load Hardware Hardware Hardware Hardware
Meltdown Variant 3a Rogue System Register Read MCU* Firmware Firmware Firmware
  Variant 4 Speculative Store Bypass Hardware + OS Firmware + OS Firmware + OS Firmware + OS
  Variant 5 L1 Terminal Fault Hardware Hardware Hardware Hardware

The fix for V3a has now changed from ‘Firmware’ to ‘MCU’, suggesting that Intel has added a microcontroller as a fix. We have asked Intel for clarification. Intel is now claiming that V4 is fixed through a combination of hardware and OS fixes.

Die Thinning

One of the new features that Intel is promoting with the new Comet Lake processors is die thinning – taking layers off of the silicon and in response making the integrated heat spreader thicker in order to enable better thermal transfer between silicon and the cooling. Because modern processors are ‘flip-chips’, the bonding pads are made at the top of the processor during manufacturing, then the chip is flipped onto the substrate. This means that the smallest transistor features are nearest the cooling, however depending on the thickness of the wafer means that there is potential, with polishing to slowly remove silicon from this ‘rear-end’ of the chip.

In this slide, Intel suggests that they apply die thinning to products using STIM, or a soldered thermal interface. During our briefing, Intel didn’t mention if all the new processors use STIM, or just the overclockable ones, and neither did Intel state if die thinning was used on non-STIM products. We did ask how much the die is thinned by, however the presenter misunderstood the question as one of volume (?). We’re waiting on a clearer answer.

Overclocking Tools and Overclocking Warranties

For this generation, Intel is set to offer several new overclocking features.

First up is allowing users to enable/disable hyperthreading on a per-core basis, rather than a whole processor binary selection. As a result, users with 10 cores could disable HT on half the cores, for whatever reason. This is an interesting exercise mostly aimed at extreme overclockers that might have single cores that perform better than others, and want to disable HT on that specific core.

That being said, an open question exists as to whether the operating system is set up to identify if individual cores have hyperthreads or not. Traditionally Windows can determine if a whole chip has HT or not, but we will be interested to see if it can determine which of my threads on a 10C/15T setup are hyperthreads or not.

Also for overclocking, Intel has enabled in the specification new segmentation and timers to allow users to overclock both the PCIe bus between CPU and add-in cards as well as the DMI bus between the CPU and the chipset. This isn’t strictly speaking new – when processors were driven by FSB, this was a common element to that, plus the early Sandy Bridge/Ivy Bridge core designs allowed for a base frequency adjustment that also affected PCIe and DMI. This time around however, Intel has separated the PCIe and DMI base frequencies from everything else, allowing users to potentially get a few more MHz from their CPU-to-chipset or CPU-to-GPU link.

The final element is to do with voltage/frequency curves. Through Intel’s eXtreme Tuning Utility (XTU) and other third party software that uses the XTU SDK, users can adjust the voltage/frequency curve for their unlocked processor to better respond to requests for performance. For users wanting a lower idle power, then the voltage during idle can be dropped for different multiplier offsets. The same thing as the CPU ramps up to higher speeds.

It will be interesting to see the different default VF curves that Intel is using, in case they are per-processor, per-batch, or just generic depending on the model number. Note that the users also have to be mindful of different levels of stability when the CPU goes between different frequency states, which makes it a lot more complicated than just a peak or all-core overclock.

On the subject of overclocking warranties, even though Intel promotes the use of overclocking, it isn’t covered by the standard warranty. (Note that motherboard manufacturers can ignore the turbo recommendations from Intel and the user is still technically covered by warranty, unless the motherboard does a technical overclock on frequency.) Users who want to overclock and obtain a warranty can go for Intel’s Processor Protection Plans, which will still be available.

Motherboards, Z490, and PCIe 4.0 ??

Due to the use of the new socket, Intel is also launching a range of new motherboard chipsets, including Z490, B460, and H470. We have a separate article specifically on those, and there are a small number of changes compared to the 300 series.

The two key features that Intel is promoting to users is support for Intel’s new 2.5 GbE controller, the I225-V, in order to drive 2.5 gigabit Ethernet adoption. It still requires the motherboard manufacturer to purchase the chip and put it on the board, and recent events might make that less likely – recent news confirmed by Intel has stated that the first generation of the I225 silicon is not up to specification, and certain connections might not offer full speed (down 10 Mbps from 2500 Mbps) depending on the end-point. As a result Intel is introducing new B2 stepping silicon later this year, and we suspect all motherboard vendors to adopt this. The other new feature is MAC support for Wi-Fi 6, which can use Intel’s AX201 CNVi RF wireless controllers.

ASRock's New Z490 PG Velocita

One big thing that users will want to know about is PCIe 4.0. Some of the motherboards being announced today state that they will support PCIe 4.0 with future generations of Intel products. At present Comet Lake is PCIe 3.0 only, however the motherboard vendors have essentially confirmed that Intel’s next generation desktop product, Rocket Lake, will have some form of PCIe 4.0 support.

Now it should be stated that for the motherboards that do support PCIe 4.0, they only support it on the PCIe slots and some (very few) on the first M.2 storage slot. This is because the motherboard vendors have had to add in PCIe 4.0 timers, drivers, and redrivers in order to enable future support. The extra cost of this hardware, along with the extra engineering/low loss PCB, means on average an extra $10 cost to the end-user for this feature that they cannot use yet. The motherboard vendors have told us that their designs conform to PCIe 4.0 specifications, but until Intel starts distributing samples of Rocket Lake CPUs, they cannot validate it except to the strict specification. (This also means that Intel has not distributed early Rocket Lake silicon to the MB vendors yet.)

So purchasing a Z490 motherboard with PCIe 4.0 costs users more money, and they cannot use it at this time. It essentially means that the user is committing to upgrading to Rocket Lake in the future. Personally I would have preferred it if vendors made the current Z490 motherboards be the best Comet Lake variants they could be, and then with a future chipset (Z590?), make those the best Rocket Lake variants they could be. We will see how this plays out, given that some MB vendors are not being completely open with their PCIe 4.0 designs.

Intel’s 10th Gen Comet Lake for Desktops Comparisons and Conclusions
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  • Spunjji - Friday, May 1, 2020 - link

    Yeah, this is the bit that gets me most. Intel fans will justify their purchase into a dead architecture that somehow requires a new motherboard with "I replace the board anyway", not ever seeming to notice how that means they could have just as easily moved to a more cost-effective and future proof platform with AMD.
  • A5 - Friday, May 1, 2020 - link

    AM4 doesn't have much runway left at this point (probably the same lifespan as LGA1200). Let's not pretend any different.

    AM5 will probably be a better buy if you're one of the like 2% of people who actually replace a CPU instead of doing a system rebuild though.
  • wilsonkf - Friday, May 1, 2020 - link

    If you buy AM4 now, you can upgrade to 16+ core Ryzen 4 or 5 two to three years later, and the system could last till 2027.

    LGA1200 will not support the next CPU arch. Maybe Intel could push Rocket Lake-S to 5.5Ghz+ to edge out Zen2+, but the heat ... It is like AM3+. Yea you could upgrade to FX9590...
  • alufan - Friday, May 1, 2020 - link

    aww cmon lets not talk out of our rear to make it look like they are making a decent offer AM4 has been able to take all the Ryzen chips so far and will take the next chip as well, show me where Intel has ever done that and offered the new features and performance with a new chip including this room heater, this is 2014/5 tech stuff with a new motherboard take your blinkers off nothing has changed apart from AMD forcing intels hand
  • WaltC - Sunday, May 3, 2020 - link

    Zen 3 will likely sit on the AM4 bus--enabling users with the ability to upgrade their CPU to Zen 3, should the upgrade in their opinion be warranted. With Intel in this case, what's notable, but not really in a positive way, is that these CPUs are barely a step up from Intel's last gen--more like a sideways step--so who wants to buy into a new mobo just to run yesterday's CPUs? It's not the question of replacing the mobo so much as it is having nothing much to put into the new mobo after you buy it, imo.
  • Spunjji - Monday, May 4, 2020 - link

    It's how many different things about A5's comment that were just plain daft. They didn't say much, and yet squeezed in so much disinformation...
  • Spunjji - Monday, May 4, 2020 - link

    Who's "pretending any different"? There's at least one more CPU line to come on AM4, which is one more than you get on 90% of Intel platforms.

    In point of fact, Intel hasn't offered a platform with even remotely similar longevity to AM4 since the 440BX, and even then a lot of its useful life was via unsupported mods and certainly wasn't intentional.
  • Spunjji - Monday, May 4, 2020 - link

    Citing stats that are the result of a decision as proof of the worth of the decision is always a dodgy proposition too... I think many more people would upgrade their CPU *if they could*. But they don't expect to, because they can't, so they don't.

    Regardless, this is a site for enthusiasts, after all, not 90% of the market. Dumb argument is dumb.
  • BenSkywalker - Saturday, May 2, 2020 - link

    AMD needs quite a bit more work on their platform to be as smooth as Intel. One downside to all the Ryzen hype is non apologists buying the platform.

    Boot times are comically slow without diving into the UEFI, even with a good NVME drive default boot was *significantly* slower than an ancient Pentium G with SSD and under no circumstances can I get it to boot faster then a very old 4570k system.

    Can't read RAM properly, no matter the setting can't get the RAM to run its rated and supported speed by default. 3200 running at 2133 using every setting except manual which resultsin a 10%-15% performance penalty.... Do we need to bring dip switches back for AMD? Reading RAM and setting it properly too much to ask from a high end chipset in 2020?
  • WaltC - Sunday, May 3, 2020 - link

    Sorry, but not a single thing you've written applies to my AMD systems...;) Your generalizing about all AMD systems is very amusing--considering I haven't had a single problem you relate. I boot to desktop Win10x 64 in ~10 seconds, from a cold boot. You find that comical, I gather. You don't have to "dive into the UEFI" at all...;) You simply do what Win10 has mandated for years and format your drive as GPT/UEFI --which is done automatically by Win10 install--no intervention needed by the user. As for your ram problems--I have no idea what your are talking about--I run XMP effortlessly--always have--since my first Zen1, actually. Right now my DDR4 runs at 3733Mhz with 100% stability on my 3900X system. I was running XMP 2.0 3200MHz with my older Zen1 R5 1600 with perfect reliability.I'm guessing that one of two things, or maybe both, are germane to you: you don't have an AMD system and you are relating info from posts you have read which you believe is true; or you have no clue as to how to setup your AMD system...;)

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