The Intel 9th Gen Review: Core i9-9900K, Core i7-9700K and Core i5-9600K Tested
by Ian Cutress on October 19, 2018 9:00 AM EST- Posted in
- CPUs
- Intel
- Coffee Lake
- 14++
- Core 9th Gen
- Core-S
- i9-9900K
- i7-9700K
- i5-9600K
Power Consumption
TDP or not the TDP, That is The Question
Notice: When we initially posted this page, we ran numbers with an ASRock Z370 board. We have since discovered that the voltage applied by the board was super high, beyond normal expectations. We have since re-run the numbers using the MSI MPG Z390 Gaming Edge AC motherboard, which does not have this issue.
As shown above, Intel has given each of these processors a Thermal Design Power of 95 Watts. This magic value, as mainstream processors have grown in the last two years, has been at the center of a number of irate users.
By Intel’s own definitions, the TDP is an indicator of the cooling performance required for a processor to maintain its base frequency. In this case, if a user can only cool 95W, they can expect to realistically get only 3.6 GHz on a shiny new Core i9-9900K. That magic TDP value does not take into account any turbo values, even if the all-core turbo (such as 4.7 GHz in this case) is way above that 95W rating.
In order to make sense of this, Intel uses a series of variables called Power Levels: PL1, PL2, and PL3.
That slide is a bit dense, so we should focus on the graph on the right. This is a graph of power against time.
Here we have four horizontal lines from bottom to top: cooling limit (PL1), sustained power delivery (PL2), battery limit (PL3), and power delivery limit.
The bottom line, the cooling limit, is effectively the TDP value. Here the power (and frequency) is limited by the cooling at hand. It is the lowest sustainable frequency for the cooling, so for the most part TDP = PL1. This is our ‘95W’ value.
The PL2 value, or sustained power delivery, is what amounts to the turbo. This is the maximum sustainable power that the processor can take until we start to hit thermal issues. When a chip goes into a turbo mode, sometimes briefly, this is the part that is relied upon. The value of PL2 can be set by the system manufacturer, however Intel has its own recommended PL2 values.
In this case, for the new 9th Generation Core processors, Intel has set the PL2 value to 210W. This is essentially the power required to hit the peak turbo on all cores, such as 4.7 GHz on the eight-core Core i9-9900K. So users can completely forget the 95W TDP when it comes to cooling. If a user wants those peak frequencies, it’s time to invest in something capable and serious.
Luckily, we can confirm all this in our power testing.
For our testing, we use POV-Ray as our load generator then take the register values for CPU power. This software method, for most platforms, includes the power split between the cores, the DRAM, and the package power. Most users cite this method as not being fully accurate, however compared to system testing it provides a good number without losses, and it forms the basis of the power values used inside the processor for its various functions.
Starting with the easy one, maximum CPU power draw.
Focusing on the new Intel CPUs we have tested, both of them go beyond the TDP value, but do not hit PL2. At this level, the CPU is running all cores and threads at the all-core turbo frequency. Both 168.48W for the i9-9900K and 124.27W for the i7=9700K is far and above that ‘TDP’ rating noted above.
Should users be interested, in our testing at 4C/4T and 3.0 GHz, the Core i9-9900K only hit 23W power. Doubling the cores and adding another 50%+ to the frequency causes an almost 7x increase in power consumption. When Intel starts pushing those frequencies, it needs a lot of juice.
If we break out the 9900K into how much power is consumed as we load up the threads, the results look very linear.
This is as we load two threads onto one core at a time. The processor slowly adds power to the cores when threads are assigned.
Comparing to the other two ‘95W’ processors, we can see that the Core i9-9900K pushes more power as more cores are loaded. Despite Intel officially giving all three the same TDP at 95W, and the same PL2 at 210W, there are clear differences due to the fixed turbo tables embedded in each BIOS.
So is TDP Pointless? Yes, But There is a Solution
If you believe that TDP is the peak power draw of the processor under default scenarios, then yes, TDP is pointless, and technically it has been for generations. However under the miasma of a decade of quad core processors, most parts didn’t even reach the TDP rating even under full load – it wasn’t until we started getting higher core count parts, at the same or higher frequency, where it started becoming an issue.
But fear not, there is a solution. Or at least I want to offer one to both Intel and AMD, to see if they will take me up on the offer. The solution here is to offer two TDP ratings: a TDP and a TDP-Peak. In Intel lingo, this is PL1 and PL2, but basically the TDP-Peak takes into account the ‘all-core’ turbo. It doesn’t have to be covered under warranty (because as of right now, turbo is not), but it should be an indication for the nature of the cooling that a user needs to purchase if they want the best performance. Otherwise it’s a case of fumbling in the dark.
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ChefJoe - Friday, October 19, 2018 - link
I have two wants.1 - I really want to see the overclocked 9600k vs overclocked 8600k, as the chart differences of it in this early draft of your 9900k-focused review are likely the wildly different clock speeds of the 86 and 96 parts.
2 - I still want to hear what happens when you drop one of these refresh parts in an older z370 board with an older bios. Do boards that were ok with 8600k refuse to boot a 9600k?
ChefJoe - Friday, October 19, 2018 - link
ack, 9700k-focused at this point. The 9900k overclock part of the review (and presumably 9600k eventually) is still pending.Ghan - Friday, October 19, 2018 - link
My plan was to upgrade from my current i7 6700k to the i7 9700k, and this article seems to confirm that my plan is a decent one. Doubling the core count from 4 to 8 is a decent value. I don't really see the point in paying an extra $100+ just for HT and slightly more cache.This release seems a bit tarnished by the fact that it is still the same process node we've had for years now. Addition of cores is great, but it's not without some cost. Still, perhaps we wouldn't even have this improvement if it weren't for AMD's strong return to the enthusiast CPU market. Hopefully the next year will be even more interesting.
Arbie - Friday, October 19, 2018 - link
"Addition of cores is great, but it's not without some cost. Still, perhaps we wouldn't even have this improvement if it weren't for AMD's strong return to the enthusiast CPU market."It's actually with a LOT of cost. And you should consider whom you're going to reward with your business: the big fat company that milked us for ten years and did everything legal and illegal to crush their competition, or the struggling firm that miraculously came from behind and reignited the market. Make your own choice, but if you buy Intel merely to have the fastest today, you're voting for sad tomorrows.
Lazlo Panaflex - Friday, October 19, 2018 - link
Well said, Arbie. Ryzen 2600 (non X) with decent stock cooler for $160 at Newegg = epic win.mapesdhs - Sunday, October 21, 2018 - link
My next new build will definitely be AMD. Looking forward to it.billin30 - Friday, October 19, 2018 - link
Maybe I am just slow in my upgrading, but my 4770k is still going strong. I am in the market for an upgrade, but I would like to see what sort of difference in performance I can expect. Its nice to see all the latest CPU's on this list, but you don't get a ton of deviation when you have CPU's that are so close in performance. It would interesting to see some benchmarks based on the previous generations top performing CPU's so we can see what sort of performance improvements we would get when moving up from past generations. I feel like a lot of people hang onto their core system components for many generations and it would be beneficial for those people to see these numbers.DanNeely - Friday, October 19, 2018 - link
This is a new set of CPU benchmarks and Ian hasn't had time to retest his other 50+ CPUs yet. From prior history that should happen as he has time and will show up as additional data points in bench.I don't think you're particularly slow about upgrading. For gaming purposes a high end CPU is reasonable to keep for 6-10 years now; possibly even a bit longer if you're only using a midrange GPU and are willing to accept the higher risk of having to build a new system with zero notice because something dies unexpectedly. I'm in a similar spot with my 4790k; and unless games needing more than 4/8 cores start becoming common am planning to keep it for at least 2 or 3 more years.
That should hopefully be long enough that Spectre stops generating frequent new exploits and mitigation is fully in hardware, that PCIe4 (or 5), DDR5, and significant numbers of USB-C ports are available. Also possibly out by then, widespread TB3, or DMI being less of a potential bottleneck on intel CPUs (either a major speedup or additional PCIe for SSDs on the CPU). Also by then either Intel should finally have it's manufacturing unfubarred or if not, AMD will likely have captured the single threaded performance crown while holding onto the multi-threaded one meaning I can have both the ST perf that many games still benefit from and the MT perf for my non-gaming uses that can go really wide.
wintermute000 - Saturday, October 20, 2018 - link
I'm haswell at 1440p too and the charts have confirmed that I'm holding on for another generation. No sense paying 1500 (32gb RAM) for a platform upgrade to get a few % more frames (and it's fine for my productivity tasks, still faster than new laptops lol)Icehawk - Saturday, October 20, 2018 - link
I only upgraded from my 4770 to an 8700 because my wife’s i5 4xxx rig died and it gave me an excuse to upgrade my encoding power. I see no difference gaming with a 970. Also I don’t notice increased performance really anywhere except encoding and decompressing during my daily use.