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Alder Lake Allegedly Commands 28% Higher Peak Current Than Rocket Lake

Image of the rear of a power supply.
(Image credit: Shutterstock)

FCPOWERUP, a Chinese media outlet that specializes in power supply reviews, has reportedly shared the power level requirements for Intel's 12th Generation Alder Lake chips. The publication has a pretty solid record in terms of leaks as it was the first to publish the schematics and photograph of Nvidia's then-unreleased 12-pin PCIe power connector.

The tables appear to have originated from one of Intel's confidential documents that's probably directed towards power supply vendors. The information allegedly specifies the power recommendations for the 12V2 power rail, which feeds the processor. Funnily enough, the table lists the specifications for 165W, 125W, 65W and 35W processors. Intel didn't port either Comet Lake or Rocket Lake to the HEDT space, so we can ignore the 165W recommendations. Furthermore, it's very unlikely that the chipmaker will launch Alder Lake in the HEDT format. At any event, take the information with a bit of salt.

The continuous current ratings for the Alder Lake 125W, 65W and 35W SKUs are identical to those of Comet Lake and Rocket Lake. The peak current ratings, however, show increases up to 28% (approximately between 50W to 100W). Peak current refers to the maximum amount of current that can be sourced during brief periods of time , while continuous current represents the amount of current that's continuously supplied.

Intel Alder Lake Power Requirements (Image credit: FCPOWERUP/Weibo)

The peak output for the 125W SKU increased from 34A (408W) to 39A (468W), while the 65W SKU went from 30A (360W) to 38.5A (462W). Even the energy-efficient 35W SKU jumped from 16.5A (198W) up to 20.5A (246W).

The transition from Rocket Lake to Alder Lake reveals a 15% higher recommended peak current capacity at the 125W tier, 28% at the 65W tier and 24% at the 35W tier. The duration depends on the PL4 of the processor. Intel specifies that the 12V2 should be able to supply peak output for 10 milliseconds. Again, it's important to emphasize that only the peak current values went up as the continuous current values remained untouched. This information is important for power supply manufacturers to ensure that their products comply with the power specifications for the upcoming Alder Lake chips.

Power supplies with a single-rail design delivers everything through a single 12V rail. The problem lies with older multi-rail power supplies where their 12V rails still adhere to the 20A (240VA) output limit. By default, the over current protection (OCP) is set to 30A and will activate for loads over 30A.

So, what does this really mean for Alder Lake adopters? FCPOWERUP noted that consumers may have to add between 50W to 100W to their power budget, depending on the exact model of the Alder Lake processor. If possible, you should opt for a power supply single-rail design as it's less likely to have that problem with the 20A limit on the 12V rails.

As we near the end of the year, more and more Alder Lake benchmarks and leaked Intel 600-series motherboards have started to pop up in the wild. Alder Lake qualification samples are secretly being sold in the Chinese black market. All these recent occurrences imply that we may see Intel's hybrid desktop chips by the end of the year, and if not then early next year.

  • peachpuff
    Just in time for winter to keep us warm
    Reply
  • Diabl0
    We have reached a point where Intel no longer cares about consumption.
    Reply
  • Co BIY
    Will this require new power supplies or is this increase well within the performance envelope of current PSUs?

    If it is a change in standards but one that all supplies already currently meet then it is no big deal.

    If it means that every Alder Lake system will require a new reworked PSU then it is a very big deal.
    Reply
  • PCWarrior
    Co BIY said:
    Will this require new power supplies or is this increase well within the performance envelope of current PSUs?

    If it is a change in standards but one that all supplies already currently meet then it is no big deal.

    If it means that every Alder Lake system will require a new reworked PSU then it is a very big deal.
    Of course they do. And all existing 500W power supplies (and above) are even capable of suppling continuous current greater than what these peak current requirements are. Also if you look at the table, Intel's 10th gen 165W cpus (these are the Cascade lake cpus like the 18-core 10980XE) have a peak current requirement of 40A. The peak current requirement for 12th gen 125W Alderlake-S (according to this leak) is 39A which is lower than that. So unless a PSU was not capable of running existing HEDT cpus at stock then it should be able to run Alderlake as well.
    Reply
  • fball922
    PCWarrior said:
    Of course they do. And all existing 500W power supplies (and above) are even capable of suppling continuous current greater than what these peak current requirements are. Also if you look at the table, Intel's 10th gen 165W cpus (these are the Cascade lake cpus like the 18-core 10980XE) have a peak current requirement of 40A. The peak current requirement for 12th gen 125W Alderlake-S (according to this leak) is 39A which is lower than that. So unless a PSU was not capable of running existing HEDT cpus at stock then it should be able to run Alderlake as well.
    That's 500w for your entire machine, though, not just to the socket. A decent GPU in the mix and you definitely need a beefy PSU to keep up with peak consumption.
    Reply
  • PCWarrior
    Peak current doesn’t mean maximum sustained current – that’s what continuous current is for. Peak current is the peak value it will reach momentarily during a transient that lasts microseconds or milliseconds. What’s important with overcurrent is heat – and there is no much heat produced even if you are pulling a KA if it only lasts a microsecond. Have you ever looked at a time-current characteristic curve of a fuse? And yes, I know, there are secondary long-term modes of failure where peak current is involved but that’s beside the point.

    And your argument of what happens when you pair it with a GPU is confusing things as you are now talking about a scenario where sustained power can exceed the power rating of the PSU. Sure, if you have a 125W cpu with a PL2 limit of 228W (19A@12V) and you unlock power limits and run a heavy AVX512 sustained workload and at the same time you also pummel your 320W RTX 3080 (26.67A@12V) with Furmark or some other torture test, you will have a sustained power consumption of over 500W (41.67A@12V) thereby exceeding the maximum sustained power rating of your PSU (and its maximum continuous current of the rail at 12V) . But peak current doesn’t come into consideration whatsoever. You would still be running out of Watts (or continuous amps in the 12V) in such scenario regardless of the momentarily peak current value.
    Reply
  • JayNor
    Alder Lake does not have avx512.

    It does have pcie5 and ddr5 io, both features supporting significantly higher data rates than supported by Intel's prior chips, so would be expected to require higher power than the pcie4 ddr4 chips while running io at full rate.

    It also has the Gracemont small cores, so there is the potential to run at lower power when not doing compute intensive or io intensive tasks.

    Samsung created some laptops with TGL that can be switched to fanless operation. I suspect that will be even easier with Alder Lake, just by turning off its Golden Cove cores.
    Reply
  • dalek1234
    No surprise there.

    Intel is doing now with CPUs, what AMD was doing with GPUs (to keep up with Nvidia). I.e: Large increases in power draw compared to past gen, to get a bit more performance. It was a desperate act for AMD to do in the past to keep up with Nvidia (not the case anymore though), and now Intel is doing the same desperate act to keep with to AMD.

    The problem here is, however, that when AMD was trying to stay competitive with Nvidia, AMD was selling their video cards for same or less than Nvidia's (performance being equal between the two). Meanwhile, Intel's processors, being inferior to AMDs, are mostly selling for more than what AMD is asking for. And if you take the total-cost-of-ownership of a CPU into perspective, including the electricity cost, a cheaper to buy Intel CPU (not that many - mostly low end) becomes more expensive because of the need to pay for the extra electricity to power them over their lifetime.

    Intel is hurting. It will take them another ~3/4 years to catch up even if they throw ton of money at the problem, because AMD isn't standing still. In the meantime, buy some AMD shares and sell them when it look like Intel is about to come up with something competitive....maybe 2024/2025
    Reply
  • Tom Sunday
    At this point I don't really care about either AMD or INTEL coming out with more powerful or refreshed desktop CPU chips. Per Gartner Research, desktop PC shipments have been dropping steadily from 157 million shipped worldwide in 2010 to just 79 million in 2020. Any PC growth at all in 2020 was strictly based on the robust mobile PC market, with "mobile PCs" showing a 49% growth.

    NVIDIA it seems puts no real value on add-in PC desktop type GPU's either. It's more money in their pockets to overwhelmingly produce automotive, cellular, consumer appliances, router and laptop chips which have a market share of over 90%. This is what people really need, want and can't do without. A recent 'Nikkei Asia' report indicated: "As to NVIDIA 96% of their customers would never buy any type of 'discrete' GPU unless its baked into the MB."

    For the better part of a decade, for me it has always been a Alienware laptop all of the time. Or using my company laptop at same time. Occasionally I started working from the desktop PC that had been gathering dust in my home office. No thank you. Then recently I purchased a premium 4K chromebook for further easy use in my kitchen, garden and prolonged waiting at the DMV. I am by nature a very selfish person and want instant convenience, 100% portability and availability.

    I am thus confident that mobiles will continue to be the preferred computing method for the masses. Working from a physical office and working from home, (WFH being the new norm) desktop PCs will even further lose out in the marketplace. I guess it's called reality and not good news for the dinosaur which the desktop PC has already become or is surely heading for! I myself surely do not like such a reality, but it is what it is!
    Reply