Package Improvements

As we move to smaller process nodes, the thermal density of high-performance silicon becomes more of an issue, and so all the processor companies put resources into their mechanical design teams to come up with a solution for the best thermal performance but also comes in line with costs. For example, we’ve seen Intel over the years transition from a soldered down heatspreader, to liquid metal, to basic thermal paste (because saving 0.1 cents means a lot across 70m CPUs), and then all the way back again when customers started demanding it.

However, in that time, we’ve pretty much kept the same socket design for mainstream processors. There hasn’t been much emphasis on changing the design itself for thermomechanical improvements in order to retain reuse and compatibility. There have been some minor changes here and there, such as substrate thinning, but nothing that substantial. The move to a new socket for Alder Lake now gives Intel that opportunity.

For Alder Lake, Intel is using an optimized packaging process to reduce the amount of soldered thermal material used in the processors. Combining that with a thinner die, and Intel is having to increase the thickness of the heatspreader to maintain the required z-height for the platform. The idea here is that the limiting factor in the cooling solution is any time we have a thermal interface, from one material to another – in this case, die to solder, and solder to heatspreader. Solder is the weak point here, so if the heatspreader gets thicker to meet the die, then less solder is needed.

Ultimately direct-die liquid cooling would be the boon here, but Intel has to come up with a solution that fits millions of processors. We have seen Intel offer different packaging solutions based on the SKU itself, so it will be interesting if the mid-range still get the Thin Die + Thin STIM treatment, or if they’ll go back to the cheap thermal paste.

Overclocking: We Have Headroom

It wouldn’t be too much of a leap to say that for most users, the only useful overclocking they might want to look at is enabling XMP on their memory. Modern processors these days are so close to their actual voltage and thermal limits out of the box these days that even if there was 200-300 MHz to gain, especially for the top Core i9 parts, it wouldn’t be worth the +100W it produces. I’m also getting to an age now where I prefer a good stable system, rather than eking out every frame, but having lived in the competitive OC scene for a while, I understand the drive that a lot of those users have to go above and beyond. To that end, Intel is introducing a few new features, and reviving some old ones, for Alder Lake.

Alder Lake also complicates things a bit with the P-core and E-core design.

To start, all the cores on the K/KF parts can be overclocked. The P-cores can be overclocked individually, whereas the E-cores are in groups of four. All the E-cores can be disabled, but at least one P-core needs to be enabled for the system to work (this has interesting consequences for Intel’s design). All cores can have additional AVX offsets, per-core ratio and voltage controls, and the ring/uncore ratios can also be adjusted. Memory also has the bells and whistles mentioned on a previous page. Those with integrated graphics can also be adjusted.

What Alder Lake brings back to the table is BCLK overclocking. For the last decade or so, most overclocking is done with the CPU multiplier, and before that it was BCLK or FSB. Intel is now saying that BCLK overclocking has returned, and this is partly due to motherboard customizations in the clock generator. Every Alder Lake CPU has an internal BCLK/clock generator it can use, however motherboard vendors can also apply an external clock generator. Intel expects only the lowest-end motherboards will not have an external generator.

The use of two generators allows the user to overclock the PCIe bus using the external generator, while maintaining a regular BCLK on other parts of the system with the internal clock. The system can also apply voltage in an adaptive way based on the overclock, with additional PLL overrides.

On top of this, Intel is integrating more user-accessible telemetry for its cores, particularly the E-cores, and real-time frequency analysis. On top of this, users can adjust the memory frequency in the operating system, rather than having to reboot – this is an extension of the memory turbo functionality previously mentioned.

For regular users, Intel is also offering a one-click immediate overclock feature. On launch, the Core i9 will be supported and overclock the P-cores +100 MHz and the E-cores +300 MHz immediately. It sounds like Intel is confident that all CPUs will be able to do this, but they want it to be user selectable. Beyond that, I confirmed the tool does still void the warranty. Intel’s VP dismissed it as an issue, citing that the recent overclocker warranty program they canned had such a low pickup, it wasn’t worth continuing. I’d say that the two things are mutually exclusive, but that’s up to Intel.

DDR5: Detailed Support, XMP, Memory Boost Performance and Conclusions
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  • Hifihedgehog - Wednesday, October 27, 2021 - link

    Most people don't care about your $10.00 in energy savings.
  • Teckk - Wednesday, October 27, 2021 - link

    Why even go with big little/power and efficiency cores in desktop then if energy doesn’t even matter?
  • Hifihedgehog - Wednesday, October 27, 2021 - link

    I agree there. I would much rather see all performance cores on a desktop SKU. big.LITTLE makes more sense in a mobile application where battery life and standby power are important.
  • The Hardcard - Wednesday, October 27, 2021 - link

    But isn’t about more power? Aren’t nearly all workloads that can peg more than six cores parallelized? What exceptions are there?

    So you have 4 E- cores in the space of one P - core and those E - cores boost muti-threaded performance. When iwould a ninth or higher P -core count do better?
  • nandnandnand - Wednesday, October 27, 2021 - link

    The efficiency cores are essentially Comet Lake cores but at lower clocks and no hyperthreading. They can fit many of them onto the die. For highly multi-threaded workloads, the more efficiency cores the better. Which is why Intel will be doubling them for Raptor Lake, and maybe doubling them again after that.

    Intel is betting you won't need more than 8 performance cores because they will handle up to 8 (or 16) single-thread sensitive tasks. Even games that can use at least 8 cores probably don't treat all of the threads as if they need the highest clocks 100% of the time.

    It could take multiple generations before Intel has a good reason to bump performance cores to 12.
  • Spunjji - Thursday, October 28, 2021 - link

    This has been mentioned enough times that people should know, but to be clear, the E cores are there to boost multithreaded performance without bloating the die size.
  • kwohlt - Wednesday, October 27, 2021 - link

    Because given the choice between 10 pCores OR 8 pCores + 8 eCores (given the same power and thermal constraints), the 8+8 build is not only offering better performance in most workloads, it's also more scalable (see Raptor Lake doubling eCores again next week, so 13600K = 6+8, 13700K = 8+8, 13900K = 8+16).
  • Mikewind Dale - Wednesday, October 27, 2021 - link

    I could see big.LITTLE being beneficial for corporations with large numbers of computers, where everyone is using basic applications like Chrome, Word, etc. The efficiency cores could save the corporation a lot of electricity and cooling costs.

    But for workstations performing tasks like video-editing, the efficiency cores may not be worthwhile.
  • nandnandnand - Wednesday, October 27, 2021 - link

    I could see businesses using the cheaper 6-core die (i5-12400) with no efficiency cores.

    The Alder Lake 2+8 ultra mobile die put in an all-in-one or small form factor mini PC would also be a good choice. That die has up to 96 graphics EUs.

    Workstation users should eventually be using efficiency cores. Just imagine if Intel made a CPU with 8-16 performance cores and 128-256 efficiency cores. If an application can scale to use hundreds of cores, you want hundreds of efficiency cores.
  • Teckk - Thursday, October 28, 2021 - link

    The peak power consumption doesn't seem to fit the case. Why even go for this for basic apps, where an i5 would do just fine?

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