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
Power Consumption: AVX-512 Caution
I won’t rehash the full ongoing issue with how companies report power vs TDP in this review – we’ve covered it a number of times before, but in a quick sentence, Intel uses one published value for sustained performance, and an unpublished ‘recommended’ value for turbo performance, the latter of which is routinely ignored by motherboard manufacturers. Most high-end consumer motherboards ignore the sustained value, often 125 W, and allow the CPU to consume as much as it needs with the real limits being the full power consumption at full turbo, the thermals, or the power delivery limitations.
One of the dimensions of this we don’t often talk about is that the power consumption of a processor is always dependent on the actual instructions running through the core. A core can be ‘100%’ active while sitting around waiting for data from memory or doing simple addition, however a core has multiple ways to run instructions in parallel, with the most complex instructions consuming the most power. This was noticeable in the desktop consumer space when Intel introduced vector extensions, AVX, to its processor design. The concurrent introduction of AVX2, and AVX512, means that running these instructions draws the most power.
AVX-512 comes with its own discussion, because even going into an ‘AVX-512’ mode causes additional issues. Intel’s introduction of AVX-512 on its server processors showcased that in order to remain stable, the core had to reduce the frequency and increase the voltage while also pausing the core to enter the special AVX-512 power mode. This made the advantage of AVX-512 suitably only for strong high-performance server code. But now Intel has enabled AVX-512 across its product line, from notebook to enterprise, with the running AI code faster, and enabling a new use cases. We’re also a couple of generations on from then, and AVX-512 doesn’t get quite the same hit as it did, but it still requires a lot of power.
For our power benchmarks, we’ve taken several tests that represent a real-world compute workload, a strong AVX2 workload, and a strong AVX512 workload.
Starting with the Agisoft power consumption, we’ve truncated it to the first 1200 seconds as after that the graph looks messy. Here we see the following power ratings in the first stage and second stage:
- Intel Core i9-11900K (1912 sec): 164 W dropping to 135 W
- Intel Core i7-11700K (1989 sec): 149 W dropping to 121 W
- Intel Core i5-11600K (2292 sec): 109 W dropping to 96 W
- AMD Ryzen 7 5800X (1890 sec): 121 W dropping to 96 W
So in this case, the heavy second section of the benchmark, the AMD processor is the lowest power, and quickest to finish. In the more lightly threaded first section, AMD is still saving 25% of the power compared to the big Core i9.
One of the big takeaways from our initial Core i7-11700K review was the power consumption under AVX-512 modes, as well as the high temperatures. Even with the latest microcode updates, both of our Core i9 parts draw lots of power.
The Core i9-11900K in our test peaks up to 296 W, showing temperatures of 104ºC, before coming back down to ~230 W and dropping to 4.5 GHz. The Core i7-11700K is still showing 278 W in our ASUS board, tempeartures of 103ºC, and after the initial spike we see 4.4 GHz at the same ~230 W.
The Core i5-11600K, with fewer cores, gets a respite here. Our peak power numbers are around the 206 W range, with the workload not doing an initial spike and staying around 4.6 GHz. Peak temperatures were at the 82ºC mark, which is very manageable. During AVX2, the i5-11600K was only at 150 W.
Moving to another real world workload, here’s what the power consumption looks like over time for Handbrake 1.3.2 converting a H.264 1080p60 file into a HEVC 4K60 file.
This is showing the full test, and we can see that the higher performance Intel processors do get the job done quicker. However, the AMD Ryzen 7 processor is still the lowest power of them all, and finishes the quickest. By our estimates, the AMD processor is twice as efficient as the Core i9 in this test.
Thermal Hotspots
Given that Rocket Lake seems to peak at 104ºC, and here’s where we get into a discussion about thermal hotspots.
There are a number of ways to report CPU temperature. We can either take the instantaneous value of a singular spot of the silicon while it’s currently going through a high-current density event, like compute, or we can consider the CPU as a whole with all of its thermal sensors. While the overall CPU might accept operating temperatures of 105ºC, individual elements of the core might actually reach 125ºC instantaneously. So what is the correct value, and what is safe?
The cooler we’re using on this test is arguably the best air cooling on the market – a 1.8 kilogram full copper ThermalRight Ultra Extreme, paired with a 170 CFM high static pressure fan from Silverstone. This cooler has been used for Intel’s 10-core and 18-core high-end desktop variants over the years, even the ones with AVX-512, and not skipped a beat. Because we’re seeing 104ºC here, are we failing in some way?
Another issue we’re coming across with new processor technology is the ability to effectively cool a processor. I’m not talking about cooling the processor as a whole, but more for those hot spots of intense current density. We are going to get to a point where can’t remove the thermal energy fast enough, or with this design, we might be there already.
I will point out an interesting fact down this line of thinking though, which might go un-noticed by the rest of the press – Intel has reduced the total vertical height of the new Rocket Lake processors.
The z-height, or total vertical height, of the previous Comet Lake generation was 4.48-4.54 mm. This number was taken from a range of 7 CPUs I had to hand. However, this Rocket Lake processor is over 0.1 mm smaller, at 4.36 mm. The smaller height of the package plus heatspreader could be a small indicator to the required thermal performance, especially if the airgap (filled with solder) between the die and the heatspreader is smaller. If it aids cooling and doesn’t disturb how coolers fit, then great, however at some point in the future we might have to consider different, better, or more efficient ways to remove these thermal hotspots.
Peak Power Comparison
For completeness, here is our peak power consumption graph.
Platform Stability: Not Complete
It is worth noting that in our testing we had some issues with platform stability with our Core i9 processor. Personally, across two boards and several BIOS revisions, I would experience BSODs in high memory use cases. Gavin, our motherboard editor, was seeing lockups during game tests with his Core i9 on one motherboard, but it worked perfectly with a second. We’ve heard about issues of other press seeing lockups, with one person going through three motherboards to find stability. Conversations with an OEM showcased they had a number of instability issues running at default settings with their Core i9 processors.
The exact nature of these issues is unknown. One of my systems refused to post with 4x32 GB of memory, only with 2x32 GB of memory. Some of our peers that we’ve spoken to have had zero problems with any of their systems. For us, our Core i7 and Core i5 were absolutely fine. I have a second Core i9 processor here which is going through stability tests as this review goes live, and it seems to be working so far, which might point that it is a silicon/BIOS issue, not a memory issue.
Edit: As I was writing this, the second Core i9 crashed and restarted to desktop.
We spoke to Intel about the problem, and they acknowledged our information, stating:
We are aware of these reports and actively trying to reproduce these issues for further debugging.
Some motherboard vendors are only today putting out updated BIOSes for Intel’s new turbo technology, indicating that (as with most launches) there’s a variety of capability out there. Seeing some of the comments from other press in their reviews today, we’re sure this isn’t an isolated incident; however we do expect this issue to be solved.
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Makste - Tuesday, April 6, 2021 - link
I again have to agree with you on this. Especially with the cooler scenario, it is not easy to spot the detail, but you have managed to bring it to the surface. Rocket Lake is not a good upgrade option now that I look at it.Oxford Guy - Wednesday, March 31, 2021 - link
(Sorry I messed up and forgot quotation marks in the previous post. 1st, 3rd, and 5th paragraphs are quotes from the article.)you wrote:
‘Rocket Lake on 14nm: The Best of a Bad Situation’
I fixed it:
Rocket Lake on 14nm: Intel's Obsolete Node Produces Inferior CPU'
‘Intel is promoting that the new Cypress Cove core offers ‘up to a +19%’ instruction per clock (IPC) generational improvement over the cores used in Comet Lake, which are higher frequency variants of Skylake from 2015.’
What is the performance per watt? What is the performance per decibel? How do those compare with AMD? Performance includes performance per watt and per decibel, whether Intel likes that or not.
‘Designing a mass-production silicon layout requires balancing overall die size with expected yields, expected retail costs, required profit margins, and final product performance. Intel could easily make a 20+ core processor with these Cypress Cove cores, however the die size would be too large to be economical, and perhaps the power consumption when all the cores are loaded would necessitate a severe reduction in frequency to keep the power under control. To that end, Intel finalised its design on eight cores.’
Translation: Intel wanted to maximize margin by feeding us the ‘overclocked few cores’ design paradigm, the same thing AMD did with Radeon VII. It’s a cynical strategy when one has an inferior design. Just like Radeon VII, these run hot, loud, and underperform. AMD banked on enough people irrationally wanting to buy from ‘team red’ to sell those, while its real focus was on peddling Polaris forever™ + consoles in the GPU space. Plus, AMD sells to miners with designs like that one.
‘Intel has stated that in the future it will have cores designed for multiple process nodes at the same time, and so given Rocket Lake’s efficiency at the high frequencies, doesn’t this mean the experiment has failed? I say no, because it teaches Intel a lot in how it designs its silicon’
This is bad spin. This is not an experimental project. This is product being massed produced to be sold to consumers.
Oxford Guy - Wednesday, March 31, 2021 - link
One thing many are missing, with all the debate about AVX-512, is the AVX-2 performance per watt/decibel problem:'The rated TDP is 125 W, although we saw 160 W during a regular load, 225 W peaks with an AVX2 rendering load, and 292 W peak power with an AVX-512 compute load'
Only 225 watts? How much power does AMD's stuff use with equivalent work completion speed?
Hifihedgehog - Thursday, April 1, 2021 - link
"The spin also includes the testing, using a really loud high-CFM CPU cooler in the Intel and a different quieter one on the AMD."Keep whining... You'll eventually tire out.
https://i.imgur.com/HZVC03T.png
https://i.imgflip.com/53vqce.jpg
Makste - Tuesday, April 6, 2021 - link
Isn't it too much for you to keep posting the same thing over and over?Oxford Guy - Wednesday, March 31, 2021 - link
Overclocking support page still doesn’t mention that Intel recently discontinued the overclocking warranty, something that was available since Sandy Bridge or something. Why the continued silence on this?‘On the Overclocking Enhancement side of things, this is perhaps where it gets a bit nuanced.’
How is it an ‘enhancement’ when the chips are already system-melting hot? There isn't much that's nuanced about Intel’s sudden elimination of the overclocking warranty.
‘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’
It also helps when people use extremely loud very high CFM coolers for their tests. Intel pioneered the giant hidden fridge but deafness-inducing air cooling is another option.
How much performance will buyers find in the various hearing aids they'll be in the market for? There aren't any good treatments for tinnitus, btw. That's a benefit one gets for life.
‘Intel uses one published value for sustained performance, and an unpublished ‘recommended’ value for turbo performance, the latter of which is routinely ignored by motherboard manufacturers.’
It’s also routinely ignored by Intel since it peddles its deceptive TDP.
‘This is showing the full test, and we can see that the higher performance Intel processors do get the job done quicker. However, the AMD Ryzen 7 processor is still the lowest power of them all, and finishes the quickest. By our estimates, the AMD processor is twice as efficient as the Core i9 in this test.’
Is that with the super-loud very high CFM cooler on the Intel and the smaller weaker Noctua on the AMD? If so, how about a noise comparison? Performance per decibel?
‘The cooler we’re using on this test is arguably the best air cooling on the market – a 1.8 kilogram full copper ThermalRight Ultra Extreme, paired with a 170 CFM high static pressure fan from Silverstone.’
The same publication that kneecapped AMD’s Zen 1 and Zen 2 but refusing to enable XMP for RAM on the very dubious claim that most enthusiasts don’t enter BIOS to switch it on. Most people are going to have that big loud cooler? Does Intel bundle it? Does it provide a coupon? Does the manual say you need cooler from a specific list?
BushLin - Wednesday, March 31, 2021 - link
I won't argue with the rest of your assessment but given these CPUs are essentially factory overclocked close to their limits, the only people who'd benefit from an overclocking warranty are probably a handful of benchmark freaks doing suicide runs on LN2.Oxford Guy - Thursday, April 1, 2021 - link
That’s why I said the word ‘enhancement’ seems questionable.Oxford Guy - Wednesday, March 31, 2021 - link
‘Anyone wanting a new GPU has to actively pay attention to stock levels, or drive to a local store for when a delivery arrives.’You forgot the ‘pay the scalper price at retail’ part. MSI, for instance, was the first to raise its prices across the board to Ebay scalper prices and is now threatening to raise them again.
‘In a time where we have limited GPUs available, I can very much see users going all out on the CPU/memory side of the equation, perhaps spending a bit extra on the CPU, while they wait for the graphics market to come back into play. After all, who really wants to pay $1300 for an RTX 3070 right now?’
• That is the worst possible way to deal with planned obsolescence.
14nm is already obsolete. Now, you’re adding in wating for a very long time to get a GPU, making your already obsolete CPU really obsolete by the time you can get one. If you’re waiting for reasonable prices for GPUs you’re looking at, what, more than a year of waiting?
‘Intel’s Rocket Lake as a backported processor design has worked’
No. It’s a failure. The only reasons Intel will be able to sell it is because AMD is production-constrained and because there isn’t enough competition in the x86 space to force AMD to cut the pricing of the 5000 line.
Intel also cynically hobbled the CPU by starving it of cores to increase profit for itself, banking that people will buy it anyway. It’s the desktop equivalent of Radeon VII. Small die + way too high clock to ‘compensate’ + too-high price = banking on consumer foolishness to sell them (or mining, in the case of AMD). AVX-512 isn’t really going to sell these like mining sold the Radeon VII.
‘However, with the GPU market being so terrible, users could jump an extra $100 and get 50% more AMD cores.’
No mention of power consumption, heat, and noise. Just ‘cores’ and price tag.
Oxford Guy - Wednesday, March 31, 2021 - link
'Intel could easily make a 20+ core processor with these Cypress Cove cores, however the die size would be too large to be economical'Citation needed.
And, economical for Intel or the customer?
Besides, going from 8 cores to 20+ is using hyperbole to distract from the facts.
'and perhaps the power consumption when all the cores are loaded would necessitate a severe reduction in frequency to keep the power under control.'
The few cores + excessive clocks to 'compensate' strategy is a purely cynical one. It always causes inferior performance per watt. It always causes more noise.
So, Intel is not only trying to feed us its very obsolete 14nm node, it's trying to do it in the most cynical manner it can: by trying to use 8 cores as the equivalent of what it used to peddle exclusively for the desktop market: quads.
It thinks it can keep its big margins up by segmenting this much, hoping people will be fooled into thinking the bad performance per watt from too-high clocks is just because of 14nm — not because it's cranking too few cores too high to save itself a few bucks.
Intel could offer more cores and implement as turbo with a gaming mode that would keep power under control for gaming while maximizing performance. The extra cores would presumably be able to do more work for the watts by keeping clocks/voltage more within the optimal range.
But no... it would rather give people the illusion of a gaming-optimized part ('8 cores ought to be enough for anyone') when it's only optimized for its margin.