Intel Shares PL1, PL2, and Tau Values on 10th Generation CPUs
Ever since before Intel launched its Comet Lake CPUs, there were questions about what kind of power draw these chips would maintain. Intel shared some of the values at launch, but we haven’t seen a full set of PL1, PL2, and Tau values for the entire family.
That data is now formally available from Intel, via the following datasheets. THG has compiled it into a much easier-to-read table:
PL1 is the guaranteed long-term TDP associated with the CPU’s minimum clock speed. In the case of the Core i9-10900K, Intel guarantees that the CPU will run at a minimum of 3.7GHz while dissipating 125W of energy over time. Intel guarantees 10 cores at 3.7GHz, eight cores at 3.8GHz, or six cores at 4.1GHz, which sheds a bit of light on what the tradeoff between frequency and core count looks like for the company on 14nm.
Anandtech’s power consumption test suggested that only the Core i9-10900K bumps up against these limits, with the Core i7-10700K’s power consumption peaking at 207W (versus an allowed 229W) and the Core i5-10600K peaking at 125W for a PL2 value, despite being allowed considerably more headroom.
One caveat here is that power behavior could change from motherboard to motherboard after UEFI updates. If anything, we’d say users should expect these kind of tweaks.
Below the top three chips, the PL2 values stay fairly high but tau values plummet and overall CPU TDP drops as well. This is one way Intel tries to maintain performance brackets between its CPUs, though the extent to which this is successful is uncertain because the company doesn’t require manufacturers to follow these values. It’s not uncommon for motherboard vendors to program a tau of 999 seconds and a PL2 of 999 to try and keep a CPU in boost mode for as long as possible.
Tau and PL2 are not the only values that impact a CPU’s boost state, but manipulating them aggressively can definitely improve a CPU’s performance over intended stock. This kind of clock behavior is something we watch for in reviews as a matter of course. If your CPU boosts unusually aggressively or destabilizes after running at top clock for long periods of time, it’s not a bad idea to make sure these values are set to defaults. It’s also not a bad idea to dust.
While PL2 values used to be predictable — just multiply PL1 by 1.25x — that formula no longer holds true, and the PL1 / PL2 ratio is different from part to part. You can also see part of how Intel hits the TDP values on its various chips, however — not just by limiting how high they can clock but also adjusting how long. Intel’s next-generation Rocket Lake CPUs, while still built on 14nm, are expected to feature the company’s first new 14nm CPU architecture since Skylake debuted in 2015.
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