Why CPU heat sink is designed to 125w for i9-13900K in Z2 G9 Tower?

[Keelung]

Hi,

I found that in z2 g9 tower, only 3 heat pipes installed into sink to cool 13900K.

I got the response from 400 support: it's a 125w CPU heat sink.

But 13900K PL2 power is 253w, so 13900K cannot run in full power, only half power!

[DGroves]

you need to understand how cpu's  work

the 125 watt spec is for normal operating

the "UP TO"  250 watt spec is what the cpu can produce briefly if "ALL cpu CORES" boost from the base clock to their max turbo frequency in other words it's the wattage used when overclocking

intel turbo boost will always try to overclock the performance cores that are in use up to the 250 watt limit for brief periods of time, and this is normal operation there is nothing wrong with the cpu or cpu cooler or the system itself

please read up on intel turbo boost and how newer intel cpu's overclock using the "P" performance and "E" Efficient cores on your i9-13900 cpu

and, yes installing a larger air cooled heatsink might/may allow the cpu to turbo boost for a longer period of time but it's not going to allow it to boost at max speeds constantly as the chip itself is limited in how quickly it can xfer heat into the heatsink

https://www.intel.com/content/www/us/en/products/sku/230496/intel-core-i913900k-processor-36m-cache-...

https://www.anandtech.com/show/18728/the-intel-core-i9-13900ks-review-taking-intel-s-raptor-lake-to-...

[Keelung]

Hi @DGroves,

For the system design, the heat sink should cover the max power of CPU.

In most of PCs, the heat sink can meet such design.

But in Z2 G9 Tower, there is only harl power of heat.

When I buying AMD 7950X3D CPU (PL2 power is 162w), the seller said I need at least 6-7 heat pipes in sink.

But in Z2 G9 Tower, Intel 13900K (PL2 power is 253w), only 3 heat pipes installed!

Both in AIDA64 and Intel Extreme Tuning Utility CPU stress test, the 13900K run in about 200w of the first minute, and then always run in 125w:

In our build task, we need more then ten minutes to finish. So in more than 90+% time, the CPU is run in 125w: harf power of 253w!

So, I think the root cause is THE HEAT SINK which only 3 pipes installed!

[DGroves]

again, you are incorrect in your improper method(s) of determining the wattage of your installed cpu

please read up on the intel turbo boost so you can understand how it functions and interacts with newer intel cpu's that have "P" and "E" cores

as i stated there is nothing wrong with your current cpu cooler it's more than capable of properly cooling the cpu

https://www.intel.com/content/www/us/en/support/articles/000088604/processors/intel-core-processors....

https://www.intel.com/content/www/us/en/gaming/resources/turbo-boost.html

[Keelung]

I know the Z2 G9 Tower is DESIGNED for125w thermal solution, even i9-13900K (Unlimited 253w PL2 power) installed.

It's OK to DESIGN to 125w or 25w or any other thermal solutions.

It's wrong if HP HIDE this low thermal DESIGN to users.

If HP's thermal DESIGN cannot meet the max power of installed CPU, 

Then HP should make users know this LOW THERMAL DESIGN clearly.

But both I and 400 supports of China cannot found this LOW THERMAL DESIGN LIMITATIONS in official documents and introduction pages.

-------------------------------------

Or why should we spend more money to buy a WorkStation in which a "K" CPU installed?

[muldashev]

I am also very curious about that. Unfortunately, I also use this setup. From my observations even running single core calculations in less than a minute drops frequency to ~4.2-4.6 Ghz. There is no sense in paying for i9 which cannot go above 5 Ghz. Also, case is too thin for having appropriate cooler with designed dissipation of 250 Watts. Also no space for AIO.  Is there any good solutions for cooling apart from undervolting? Did anyone find a cooler which fits in and actually can dissipate heat better than stock cooler?

Cheers

[Keelung]

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@muldashev wrote:

Did anyone find a cooler which fits in and actually can dissipate heat better than stock cooler?

As I got from 400 supporter, you cannot just upgrade the cooler only.

Because the circuit and electronic components are Designed and Tested only for 125w TDP. If you changed the cooller only, they cannot guarantee the steadness while running in high power in long time.

So, I suggest you refund. The seller agreed my return when I want to engage in a lawsuit, both to HP and the seller. 

[BogdanPatrascu]

It's simple, cutting costs. I have a Z2 G5 with i7 10700(non-K) which is rated at 65w, and it came with a 65w heatsink.

I had multiple issues with overheating and throttle because of the cooling solution.

I believe HP is choosing the cooling using the Office type of workload because once I started using 2-3 VMs on this workstation, the CPU consumption skyrocketed to around 120w to 140w. The device was throttleing all the time, stuttering, etc. The only solution was to force the service to provide me with a proper cooler for this CPU. The 125w did the trick.

I think that your best solution to keep that device in place from temp perspective, is to get a Noctua or something similar. I don't think HP has any solution for more than 125w.

[Keelung]

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@BogdanPatrascu wrote:

It's simple, cutting costs. 

I think so too.

But HP should make customers known that, in sell page / introduce page / datasheet and so on. Confirmed with 400 support, there is no such official declaration.

If HP hide this limitation, then the customers will think HP can handle the max power of CPU since it's a desktop workstation in which a -K CPU installed, but that's wrong and breaking user's normal IT knowledge.

I don't know whether is hiding info is illegal or not, since I'm not a layer of IT.

For a better cooler, as warned from 400 support, HP cannot promise the system stability, since the PCB board and connected components are not DESIGNED and not TESTED for more larger current. And, the BIOS may limit the power usage too. Anyway, you can test it and take response from you but HP: Any issues caused by unofficial component isn't the bussiness of HP.

[BogdanPatrascu]

Hi Keelung,

For me, any brand workstation without a proper description and hardware details is a no-go.

Usually for Workstation class devices, especially desktops, i go with custom builds, i know it's easier to manage a fleet of brand devices, but when it comes to raw power and flexibility, brand-name computers are a no-go. They are limiting your upgrades and options.