Intel Rocket Lake (14nm) Review: Core i9-11900K, Core i7-11700K, and Core i5-11600K
by Dr. Ian Cutress on March 30, 2021 10:03 AM EST- Posted in
- CPUs
- Intel
- LGA1200
- 11th Gen
- Rocket Lake
- Z590
- B560
- Core i9-11900K
Intel’s New Adaptive Boost Technology for Core i9-K/KF
Taken from our news item
To say that Intel’s turbo levels are complicated to understand is somewhat of an understatement. Trying to teach the difference between the turbo levels to those new to measuring processor performance is an art form in of itself. But here’s our handy guide, taken from our article on the subject.
Adaptive Boost Technology is now the fifth frequency metric Intel uses on its high-end enthusiast grade processors, and another element in Intel’s ever complex ‘Turbo’ family of features. Here’s the list, in case we forget one:
| Intel Frequency Levels | ||
| Base Frequency | - | The frequency at which the processor is guaranteed to run under warranty conditions with a power consumption no higher than the TDP rating of the processor. |
| Turbo Boost 2.0 | TB2 | When in a turbo mode, this is the defined frequency the cores will run at. TB2 varies with how many cores are being used. |
| Turbo Boost Max 3.0 | TBM3 'Favored Core' |
When in a turbo mode, for the best cores on the processor (usually one or two), these will get extra frequency when they are the only cores in use. |
| Thermally Velocity Boost | TVB | When in a turbo mode, if the peak thermal temperature detected on the processor is below a given value (70ºC on desktops), then the whole processor will get a frequency boost of +100 MHz. This follows the TB2 frequency tables depending on core loading. |
| Adaptive Boost Technology | ABT 'floating turbo' |
When in a turbo mode, if 3 or more cores are active, the processor will attempt to provide the best frequency within the power budget, regardless of the TB2 frequency table. The limit of this frequency is given by TB2 in 2-core mode. ABT overrides TVB when 3 or more cores are active. |
| *Turbo mode is limited by the turbo power level (PL2) and timing (Tau) of the system. Intel offers recommended guidelines for this, but those guidelines can be overridden (and are routinely ignored) by motherboard manufacturers. Most gaming motherboards will implement an effective ‘infinite’ turbo mode. In this mode, the peak power observed will be the PL2 value. It is worth noting that the 70ºC requirement for TVB is also often ignored, and TVB will be applied whatever the temperature. | ||
Intel provided a slide trying to describe the new ABT, however the diagram is a bit of a mess and doesn’t explain it that well. Here’s the handy AnandTech version.
First up is the Core i7-11700K that AnandTech has already reviewed. This processor has TB2, TBM3, but not TVB or ABT.
The official specifications show that when one to four cores are loaded, when in turbo mode, it will boost to 4.9 GHz. If it is under two cores, the OS will shift the threads onto the favored cores and Turbo Boost Max 3.0 will kick in for 5.0 GHz. More than four core loading will be distributed as above.
On the Core i9-11900, the non-overclocking version, we also get Thermal Velocity Boost which adds another +100 MHz onto every core max turbo, but only if the processor is below 70ºC.
We can see here that the first two cores get both TBM3 (favored core) as well as TVB, which makes those two cores give a bigger jump. In this case, if all eight cores are loaded, the turbo is 4.6 GHz, unless the CPU is under 70ºC, then we get an all-core turbo of 4.7 GHz.
Now move up to the Core i9-11900K or Core i9-11900KF, which are the only two processors with the new floating turbo / Adaptive Boost Technology. Everything beyond two cores changes and TVB no longer applies.
Here we see what looks like a 5.1 GHz all-core turbo, from three cores to eight cores loaded. This is +300 MHz above TVB when all eight cores are loaded. But the reason why I’m calling this a floating turbo is because it is opportunistic.
What this means is that, if all 8 cores are loaded, TB2 means that it will run at 4.7 GHz. If there is power budget and thermal budget, it will attempt 4.8 GHz. If there is more power budget and thermal budget available, it will go to 4.9 GHz, then 5.0 GHz, then 5.1 GHz. The frequency will float as long as it has enough of those budgets to play with, and it will increase/decrease as necessary. This is important as different instructions cause different amounts of power draw and such.
If this sounds familiar, you are not wrong. AMD does the same thing, and they call it Precision Boost 2, and it was introduced in April 2018 with Zen+. AMD applies its floating turbo to all of its processors – Intel is currently limiting floating turbo to only the Core i9-K and Core i9-KF in Core 11th Gen Rocket Lake.
One of the things that we noticed with AMD however is that this floating turbo does increase power draw, especially with AVX/AVX2 workloads. Intel is likely going to see similar increases in power draw. What might be a small saving grace here is that Intel’s frequency jumps are still limited to full 100 MHz steps, whereas AMD can do it on the 25 MHz boundary. This means that Intel has to manage larger steps, and will likely only cross that boundary if it knows it can be maintained for a fixed amount of time. It will be interesting to see if Intel gives the user the ability to change those entry/exit points for Adaptive Boost Technology.
There will be some users who are already familiar with Multi-Core Enhancement / Multi-Core Turbo. This is a feature from some motherboard vendors have, and often enable at default, which lets a processor reach an all-core turbo equal to the single core turbo. That is somewhat similar to ABT, but that was more of a fixed frequency, whereas ABT is a floating turbo design. That being said, some motherboard vendors might still have Multi-Core Enhancement as part of their design anyway, bypassing ABT.
Overall, it’s a performance plus. It makes sense for the users that can also manage the thermals. AMD caught a wind with the feature when it moved to TSMC’s 7nm. I have a feeling that Intel will have to shift to a new manufacturing node to get the best out of ABT, and then we might see the feature on the more mainstream CPUs, as well as becoming default as standard.
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SystemsBuilder - Tuesday, March 30, 2021 - link
Honestly, I think they just mislabeled the 11900k and 11700k in the first 3D Particle Movement v2.1 tests result OR it's thermal throttling because they are exactly the same but architecturally (11900k higher frequencies).But the whole topic of AVX512 is interesting. It looks like Intel did not release Cypress Cove AVX-512 architecture details like they did for Sunny Cove last year (and Skylake-X cores before). But if Cypress Cove is close enough to Sunny Cove (and tit should be), they have crippled the AVX-512 quite severely but to confirm that we need to see the official Intel slides on core design. I am specifically talking about that core port 5 is crippled in Sunny Cove (compared to what Skylake-X and Cascade lake-X have) and does not include a FMA, essentially cutting the throughput in half for FP32 and FP64 workloads. Port 5 do have a ALU so Integer workloads should be running at 100% compared to Skylake-X. I really like to see Cypress Cove AVX-512 back end architecture design at the port level from Intel to understand this better though.
GeoffreyA - Tuesday, March 30, 2021 - link
I believe they added an FMA to Port 5, and combining that one and the FMA from Port 0, create a single AVX512 "port," or rather the high- and low-order bits are dispatched to 5 and 0.https://www.anandtech.com/show/14514/examining-int...
https://en.wikichip.org/w/images/thumb/2/2d/sunny_...
GeoffreyA - Tuesday, March 30, 2021 - link
I'm not fully sure but think Cypress is just Willow, which in turn was just Sunny, with changes to cache. Truly, the Coves are getting cryptic, and intentionally so.SystemsBuilder - Tuesday, March 30, 2021 - link
The official intel slide posted on this page: https://www.anandtech.com/show/14514/examining-int... (specifically this slide: https://images.anandtech.com/doci/14514/BackEnd.jp... , shows what i'm talking about. The 2nd FMA is missing on port 5 but the ALU is there - 50% of FP compute power vs. Skylake-X architecture. The other slide on wikichip is contradicting official intel slide OR it only applies to server side with full Sunny Cove enabled (usually the consumer client side version is a cut down).In any case these slides are not Cypress Cove so the question remains what have they done to AVX-512 architecture port 0+1 and port 5.
GeoffreyA - Tuesday, March 30, 2021 - link
You're right. I didn't actually look at the Intel slide but was basing it more on the Wikichip diagram and Ian's text. Will be interesting if we can find that information on Cypress C.JayNor - Tuesday, March 30, 2021 - link
"My main interest is getting the fastest single-core AVX available..."Rumors within the last week say there will be Emerald Rapids HEDT chips next yr. Not sure about Ice Lake Server workstation chips. If either of these provide dual avx512 they might be worth the wait.
SystemsBuilder - Tuesday, March 30, 2021 - link
I'm thinking Sapphire Rapids, which is due to arrive in late 2021 (very best case or, more likely, 2022), is the one to hold out for. Build on the better performing 10nm Finfet, it will add PCIe 5.0, DDR5 and further improve on AVX 512 with BF16 and AMX Advanced Matrix Extensions https://fuse.wikichip.org/news/3600/the-x86-advanc...Now, if you read about this you realize what step up for (FP and int) compute that is. Massive!
scan80269 - Tuesday, March 30, 2021 - link
It looks like Rocket Lake is the first desktop class x86 processor to support hardware acceleration for AV1 video format decode, similar to Tiger Lake for mobile. Interesting how this power hungry processor family can deliver good energy efficiency when it comes to watching 4K HDR movies/videos. OTT platform providers need to offer more content encoded in AV1, though.Hifihedgehog - Tuesday, March 30, 2021 - link
Meh... This is a fixed-function IP block for a very specific task so it is going to be low power. At this point, for most people, HEVC support is what actually matters. HEVC already offers a 50% improvement in bitrate efficiency over H.264, and AV1 only claims the same thing. Royalties or not, because HEVC was first to the game, it became the industry standard for UHD/4K Blu-ray. Timing is everything and AV1 missed the boat on that by about five years. So with the industry locked into HEVC, AV1 is going to have an incredibly hard time getting uptake outside of online streaming, which is a whole other ball of wax. And even then, as a content creator, you can use HEVC royalty free anyway if you are livestreaming on YouTube.GeoffreyA - Tuesday, March 30, 2021 - link
While AV1's quality is excellent, surpassing that of HEVC, its encoding speed is impractical for most people,* and I'm doubtful whether it's going to get much better. If people (and pirates, yes) can't use it easily, its spread will be limited. The only advantage it has, which I can vouch for anecdotally, is superior quality to HEVC. But even this advantage will be short lived, once VVC enters the fray in the form of x266. I've got no idea how x266 will perform, but from testing the Fraunhofer encoder, saw that VVC and AV1 are in the same class, VVC being slightly ahead, sharper, and faster.* libaom, the reference encoder. Intel's SVT-AV1 is faster but has terrible quality.