Asus Confirms Intel DLVR Was Fused Off in Raptor Lake

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No Digital Linear Voltage Regulator this generation

Intel XTU guide image
(Image credit: Intel)

According to a reply by Asus overclocker Shamino on the ROG forums, Intel's DLVR (Digital Linear Voltage Regulator) technology is disabled on current generation Raptor Lake processors. The tech was fused off by Intel at the factory.

The reply was made in response to an ROG forum user who asked why DLVR's feature set exits in the Z690 Hero UEFI, to which Shamino said engineering sample Raptor Lake chips did have DLVR enabled and operational, but it was fused off mid-way into development by Intel. As a result, Asus decided to leave the DLVR feature intact inside the BIOS, just in case Intel decides to bring the feature back in a future CPU architecture/generation.

DLVR is very closely related to Intel's integrated voltage regulator FIVR technology. Intel patented this technology earlier this year and confirmed its existence in the Raptor Lake CPU architecture. DLVR had the potential of reducing Raptor Lake CPU power consumption by up to 25%, if Intel had enabled the feature.

In basic terms, DLVR sits inside the CPU die and helps regulate power, operating in parallel with the voltage regulators found on the motherboard. By introducing a digital regulator so close to the CPU, voltage ripples could be reduced, thus lowering power consumption. Intel's patent says the CPU's VID, the voltage requested by the processor, can be reduced by as much as 160mv. Since power scales with the square of voltage, that's where the 20% to 25% power reduction comes from.

According to the forum post, Asus has several DLVR settings for adjusting the digital regulator's behavior on the Z690 Hero: auto, enabled, and disabled. There's also a "CPU DLVR Bypass Mode Enable" option, which Shimano says all Raptor Lake chips are fused to at the factory. It's not clear what the difference between "disabled" and "bypass" mode might have been, but the feature was cut well into the development process.

It's also unclear why Intel decided to pull the plug on DLVR during the development of Raptor Lake. We suspect the technology was too new, at least for the specific implementation in Raptor Lake. Auto-tuning of voltages can potentially cause problems if it's not done correctly. Whatever happened, it seems like we'll be seeing DLVR return at some point in the future — probably just not with Raptor Lake.

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Aaron Klotz
Aaron Klotz
Contributing Writer

Aaron Klotz is a contributing writer for Tom’s Hardware, covering news related to computer hardware such as CPUs, and graphics cards.

4 Comments Comment from the forums
  • cyrusfox
    Hope we see this in use on mobile and low power chips, wonder what adavtage is actualized. 25% sounds great!
    Reply
  • Alvar "Miles" Udell
    DLVR had the potential of reducing Raptor Lake CPU power consumption by up to 25%, if Intel had enabled the feature.


    A 20% power reduction would put it at 226.4w, the same as a Ryzen 7950X...
    Reply
  • cyrusfox
    Alvar Miles Udell said:
    A 20% power reduction would put it at 226.4w, the same as a Ryzen 7950X...
    From hothardware.com article it states it is only that effective at Sub 40Amp(Sub 40 W essentially). Gains disappear at higher amperage.

    Quote:
    However, those power savings were primarily during lower-load situations under 40A. If you're familiar with modern CPUs, 40A is usually around 40 watts. Intel's recent desktop CPUs spend most of their time well above 40 watts, and the savings from this design (by Intel's own reckoning and admission) fell off sharply past that point.
    Reply
  • JamesJones44
    cyrusfox said:
    From hothardware.com article it states it is only that effective at Sub 40Amp(Sub 40 W essentially). Gains disappear at higher amperage.

    Quote:
    However, those power savings were primarily during lower-load situations under 40A. If you're familiar with modern CPUs, 40A is usually around 40 watts. Intel's recent desktop CPUs spend most of their time well above 40 watts, and the savings from this design (by Intel's own reckoning and admission) fell off sharply past that point.

    This article seems to indicate that their estaminets include going above 40A in normal cycles.
    Once the CPU current consumption exceeds 40A, some of the D-LVR power gates activate to supply the additional current to the Vin. For example, at 45A, the motherboard VR sends 40A, while the D-LVR power gates administers the extra 5A. The D-LVR power gates consume very little energy, assuming that the duration and duty cycle above 40A is short. With Intel's example, we can expect a 21% decrease in CPU power, which translates to roughly to a 7% performance uplift.

    Buy yeah, in your Blender, Cinebench, Geekbench, etc. it probably doesn't make as big of a difference. However, I don't like those tests as they do not replicate normal workloads, just worst case scenarios which doesn't really give a clear picture (good or bad) of how well the CPU will work for a build, but I degrees.
    Reply