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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  • Deicidium369 - Saturday, May 2, 2020 - link

    or used the TSMC method like 16nm, 16nm+ = 14nm, 16nm++ = 12nm

    If you think the latest Intel 14nm is still 14nm you are a bit dense... probably closer to 12 or 11nm
  • Spunjji - Monday, May 4, 2020 - link

    The latest 14nm variants are *less dense* than the originals in order to reach higher clocks. They're objectively superior in performance to the old versions of the node, but your comparison is asinine from anything other than a cheerleading perspective.
  • Haawser - Friday, May 1, 2020 - link

    Expensive new motherboard + 14nm nuclear reactor ? Meh, no thanks. The advantages over Coffee lake or Ryzen 3000 are minimal at best, and simply not worth the heat, noise, power and cost.
  • Deicidium369 - Saturday, May 2, 2020 - link

    I can see nothing in Comet Lake to abandon core i9 9900K - zero reason to move to CML
  • 137ben - Friday, May 1, 2020 - link

    I think the article overlooks one key area in which these new Intel processors outdo current Ryzen offerings: more cores with integrated graphics. There are applications that are heavy on CPU/memory usage but don't get much benefit from GPU. For those use cases, having integrated graphics to run the operating system's UI is a cost-saver.

    The current top-of-the-line AMD APUs come with 4 cores/8 threads (AFAIK?). The newly announced i5-1050 0 comes with 6C/12T and for more money you can get an 10C/20T i9-10900 without needing to buy an extra graphics card.

    Of course, if you are doing any graphics-heavy tasks like AAA gaming, then it doesn't matter because you'll have to buy a discrete GPU anyways. But for the niche of CPU-bounded computing paired with integrated graphics, Intel appears to be back on top, at least until AMD starts rolling out Zen 2 APUs.
  • willis936 - Friday, May 1, 2020 - link

    You can get a cheap dGPU with comparable performance to an iGPU for the cost of a CPU cooler that could keep one of these puppies from throttling.

    What matters is price and performance. They're redlining their engine to keep up with performance (consumer die lapping???) and are having to charge an almost sane price for the first time in a decade. It won't save them if they can't keep up with the process node though.
  • Deicidium369 - Saturday, May 2, 2020 - link

    And OEMs don't want to add yet another product to the BoM - and OEM customers don't want another component to support and deal with - most businesses are perfectly fine with the iGPUs in Intel - no additional component to support.
  • Spunjji - Monday, May 4, 2020 - link

    Which is worse - BoM for a passively-cooled dGPU from a company that actually provides reliable drivers, or BoM for the up-rated CPU cooler, additional system fans and beefier PSU required to support Intel's latest at anything like its rated speeds?

    Of course OEMs will probably make the decision you're suggesting they'll make, because they're incentivized not to switch vendors. They'll more than likely just supply the CPUs in systems that are utterly incapable of reaching their rated boost speeds for longer than a few milliseconds, just like they've been doing in notebooks ever since Kaby Lake R came out.
  • Zizy - Friday, May 1, 2020 - link

    I don't think that really matters - in the end you want the highest performance for the lowest price. Take i9-10900 with its horrible cooler. On AMD's side you have 3900X which has a working cooler, is likely faster and costs only 30e extra for the 710GT GPU to display screen. Sure, one extra part is annoying but a small price for all the other benefits.

    Also, the only game that works better on i9 than on AMD APUs is a turn based Civ6 because time for turns is more important than framerate.
  • Deicidium369 - Saturday, May 2, 2020 - link

    OK none of these come with a cooler... so what cooler are you talking about? Typically that would be paired with a Noctua NH-D15 SSO...

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