i9-13900K CPU, Ray Tracing performance and CPU temperatures

[Barton_Brown]

Curiosity question for those with systems that use the Intel I9-13900K processor and do ray tracing: How many cores/threads in CA can you enable for ray tracing before the CPU junction temperature exceeds 80 degrees C ? 

 

I recently got my new system and was disappointed to see that even with a 3-fan liquid cooled CPU, ray tracing with more than around 8 cores/treads selected in preferences (out of 32) resulted in Tjunction of 80+ degrees C. (don't exceed 100 degrees C)

 

While the i9-13900K system is definitely faster for a lot of tasks, it turns out that the ray trace times on this system versus my older water cooled i7-6900K system with 16 cores/threads enabled has roughly similar ray trace times without the heating issues... bummer/

 

Is this heating issue to be expected with the I9? I knew it ran hot, but was not expecting the heat limitation when only a quarter of the cores are 'cranking'. Is it my system, or just a 'live with it' situation?

 

Thanks,

 

[scottharris]

For the most part I now use the PBR raytracing since it's fast and easier on my laptop.    Can this GPU raytracing replace your need for CPU raytracing?

[Renerabbitt]

On 4/5/2023 at 5:27 PM, Barton_Brown said:

Curiosity question for those with systems that use the Intel I9-13900K processor and do ray tracing: How many cores/threads in CA can you enable for ray tracing before the CPU junction temperature exceeds 80 degrees C ? 

 

I recently got my new system and was disappointed to see that even with a 3-fan liquid cooled CPU, ray tracing with more than around 8 cores/treads selected in preferences (out of 32) resulted in Tjunction of 80+ degrees C. (don't exceed 100 degrees C)

 

While the i9-13900K system is definitely faster for a lot of tasks, it turns out that the ray trace times on this system versus my older water cooled i7-6900K system with 16 cores/threads enabled has roughly similar ray trace times without the heating issues... bummer/

 

Is this heating issue to be expected with the I9? I knew it ran hot, but was not expecting the heat limitation when only a quarter of the cores are 'cranking'. Is it my system, or just a 'live with it' situation?

 

Thanks,

 

Switch to GFX card based PBR raytracing. Rendered in under a minute:
 

[DBCooper]

Rene, those are some really good renderings.  I just can't unsee the "New York" book that is backwards though. 

 

[DeLayDesign]

On 4/5/2023 at 7:27 PM, Barton_Brown said:

Curiosity question for those with systems that use the Intel I9-13900K processor and do ray tracing: How many cores/threads in CA can you enable for ray tracing before the CPU junction temperature exceeds 80 degrees C ? 

 

I recently got my new system and was disappointed to see that even with a 3-fan liquid cooled CPU, ray tracing with more than around 8 cores/treads selected in preferences (out of 32) resulted in Tjunction of 80+ degrees C. (don't exceed 100 degrees C)

 

While the i9-13900K system is definitely faster for a lot of tasks, it turns out that the ray trace times on this system versus my older water cooled i7-6900K system with 16 cores/threads enabled has roughly similar ray trace times without the heating issues... bummer/

 

Is this heating issue to be expected with the I9? I knew it ran hot, but was not expecting the heat limitation when only a quarter of the cores are 'cranking'. Is it my system, or just a 'live with it' situation?

 

Thanks,

 

Although I'm not a PC buff when it comes to builds, I did just recently have to replace my AIO cooling system which sounds similar to a system you're using. (liquid cooled - three fans; but have a total of 9 fans in the case)

You may want to look at your cooling system to see if it's functioning correctly.  I only do GPU renders for exteriors when I have used the old '2D' plants that don't cast shadows in PBR @ChiefArchitect- looking at you (still) for a resolution on this.  That said my unit actually dropped my temp by 3 degrees Celsius when I kicked on the render. (dropping from 35 degrees to 32 degrees)  I'm thinking your cooling system is defective.

In any case - if you can you really should be using the PBR more.  It really is above and beyond the old method of rendering.

[HumbleChief]

16 hours ago, Renerabbitt said:

Switch to GFX card based PBR raytracing. Rendered in under a minute:

Apologies Rene but what is a GFX card?

 

thanks

[Renerabbitt]

32 minutes ago, HumbleChief said:

Apologies Rene but what is a GFX card?

 

thanks

Graphics card, just industry short hand

[ProPlan_2011]

18 hours ago, DBCooper said:

Rene, those are some really good renderings.  I just can't unsee the "New York" book that is backwards though. 

 

Really into the details, but true.

[para-CAD]

18 hours ago, DBCooper said:

Rene, those are some really good renderings.  I just can't unsee the "New York" book that is backwards though. 

 

I think that was intentional just to prove that it was a rendering and not a real photograph   

[HumbleChief]

1 hour ago, Renerabbitt said:

Graphics card, just industry short hand

DOH, Thanks....

[Barton_Brown]

10 hours ago, DeLayDesign said:

Although I'm not a PC buff when it comes to builds, I did just recently have to replace my AIO cooling system which sounds similar to a system you're using. (liquid cooled - three fans; but have a total of 9 fans in the case)

You may want to look at your cooling system to see if it's functioning correctly.  I only do GPU renders for exteriors when I have used the old '2D' plants that don't cast shadows in PBR @ChiefArchitect- looking at you (still) for a resolution on this.  That said my unit actually dropped my temp by 3 degrees Celsius when I kicked on the render. (dropping from 35 degrees to 32 degrees)  I'm thinking your cooling system is defective.

In any case - if you can you really should be using the PBR more.  It really is above and beyond the old method of rendering.

Adam, after some simple investigation, I do not believe the cooling system is defective but may be 'under spec'ed'. The computer is only two weeks old and was a custom build with the cooling system a slight upgrade from the recommended solution. The cooling system does a great job of keeping the CPU junction temps pretty close to ambient (plus a degree C or so) until the CPU starts working hard. When a particular core gets to 90%+ utilization, that core temp goes up to high 80 C but drops immediately when the utilization drops. The cooling air outflow from the liquid cooling and the back of the PC also gets very warm when the ray tracing is underway. For me, I think this is just a 'live with it' situation. 

 

I am a complete newbie with PBR and it looks promising although it lacks realistic shadows in some situations (probably an newbie issue). I did a couple of PBRs and the 4070 graphics card only takes a second or two to "complete the image". Good enough for my situation.

 

Thanks!

[Designers_Ink]

When I first got my system, I had similar problems with overheating.  I finally resolved the issue with buying a larger power supply than what came with the system.  I haven't had an overheating issue since.  

[Smn842]

One of my machines is i9-13900K and its on air and although it certainly runs hotter than some other CPUs its not thermally limited by any significant degree.

 

I would check the liquid cooling system for correct radiator/inlet/outlet orientation/air presence, CPU thermal compound and overall case air flow management. The last seems unimportant to many but gaps where potential inlet fans could be mounted can ruin overall air flow on what should be a positive air pressure arrangement.

 

Also bear in mind that the i9-13900K can run over 80 degrees without issue and that its a mix of 8 performance cores and 16 efficient cores with 32 total hyper threaded cores and the 6900K was 8 performance cores yielding 16 hyperthreaded cores so not all cores are equal in purpose.

 

The i9-13900K should still way outpace your older system but temps may be higher and any issue with cooling will seriously affect it.

[Electromen]

I have a one year old Liquid Cooled MSI gaming computer with NVIDIA 3080ti video card.  It was overheating and shutting down running X14.

I removed the Liquid Cooled and installed all fan based cooling.  I haven't had a problem since then.

[Kbird1]

15 hours ago, Barton_Brown said:

For me, I think this is just a 'live with it' situation

 

Well you should be following up with CyberPower for sure, since under warranty, and asking a few questions...... If allowed under Warranty I'd probably pull the AIO and reinstall it with fresh TIM (Thermal Grease) , hopefully you don't find it was forgotten or they only use the MFG's pre-applied TIM which maybe too little for a large CPU like a 13900k. 

 

With 3 fans it sounds like a 360mmm AIO ( you didn't mention brand/model ) which I'd do some research on personally re the 13900k, but I have been using Arctic Cooling's Freezer 240mm AIOs for the last 8-10yrs with no issues but the most likely scenario is, it maybe installed incorrectly or the TIM ( thermal interface Material ) is not done correctly, ie not enough or is not of high quality like Noctua's NT-H1 ( use NT-H2 on the 13900k perhaps) or Thermal Grizzly's Kyronaut. Not being an extreme Overclocker or even overclocking these days on the 11700k I have currently, I haven't noticed a performance difference in the two.

 

https://noctua.at/en/nt-h1-3-5g

https://www.youtube.com/watch?v=2lFd4l7wX3I&t=6s

 

https://www.thermal-grizzly.com/en/products

 

 

 

M.

 

[Barton_Brown]

A big THANK YOU to all that have provided input about my CPU situation. Time for me to respond....

 

Jeff Dillon suggested a possible power supply issue: The original recommended supply for the system was 850W, I upped the build to 1000W but I guess it could still be an issue...

 

There was a question about the liquid cooling system - it is the CyberPower DeepCool Castle 360 EX. Not much info available on the CyberPower website. Also the system is housed in the Phanteks Evolv X ATX mid-tower with a total of 7 fans (two front, one rear, three liquid cooling, one power supply).

 

What I did not mention previously is the system is located in a non-AC house in the tropics. Typical daytime ambient temperatures at the PC now are 30C (85F) when I have been running the test. Relative Humidity about 75%. I added an external house fan blowing directly on the front of the PC since it is presently sitting in the "computer slot" of my desk which does restrict the airflow above the PD. I ran some test ray traces and the fan alone dropped the peak junction temps by 2-3 degrees C. Running ray traces with 10 cores for 10 minutes resulted in peak junction temps of around 90C. Using 15 cores I got a couple of core temperature warnings after about 3 minutes. Idle junction temps are around 35 C. If I pause the ray trace, the junction temps drop to the low 40 degrees C within a second or two. 

 

I suspect, without any proof, that if this PC was in a 25 C environment with lower RH that I could run ray traces with 15 cores without any heating issues. 

 

Thanks again for all the helpful suggestions. I'm on 'island time' here so it could be a while before any further investigations will be completed 

[Barton_Brown]

For those that love data... 

 

Ran an A/B comparison between the 6900K and 13900K computers this morning (ambient at 27C) using the same image but CA X14 on 6900K, CA X15 on 13900K.

 

6900K, 15 cores, 2 passes took 7:14, max temp 60C, PBR took about 5 seconds using 3060 GFX card

13900K, 8 cores, 2 passes took 5:15, max temp 85C, PBR took about 2-3 seconds using 4070 GFX card

 

While it is possible that the liquid cooling performance on the 13900K PC could be improved, it is definitely working well enough for the needs of this DIYer that only needs a few ray traces at a time and has plenty of 'island time' available to get the results. . IMHO it is not worth the risk/effort for me to tear the PC apart to investigate if there might be an issue. I'll call CyberPower but pretty sure the answers I'll receive. For everything else I do on this PC, the CPU temps are typically in the mid-40 C range with "idle" temps around 32-35 C. Time to spend my spare time exploring PBRs.

 

Thanks again for all the suggestions and help.

[jtcapa1]

It is a little frustrating to read threads like these and see a bunch of comments which focus on parts and pieces instead of systems.

The best advice from a cost perspective is get a good graphics card and us PBR instead of CPU RT.

All the threads and cores of the 13900 series of CPU's are costly overkill for 99% of what we do. Not worth the money in a custom build.

Right now, for CA users, it seems like the money is better spend on a high end graphics card.  Barton, another good test is to launch task manager and just look at what the CPU is doing between the i7 cheap CPU and the i9 overpriced CPU.  Is all that money worth the extra 2 minutes you save? On island time?

[Renerabbitt]

On 4/7/2023 at 8:28 PM, DBCooper said:

Rene, those are some really good renderings.  I just can't unsee the "New York" book that is backwards though. 

 

rendered in a mirror 

[Renerabbitt]

25 minutes ago, jtcapa1 said:

Is all that money worth the extra 2 minutes you save?

Sooooo I would agree with you, until I got a machine with PCI 4 and DDR5, and now I will never use my i9 based machine again because it was on PCI3 and DDR4. The difference feels like a LOT

[jtcapa1]

I want to rant a bit here, so forgive me.

But every f**king time I watch one of those youtube influencers on computers, I go down this time consuming black hole of bright and shiny bigger, better and faster tech slides.

All I really want to know at any one point in time is 'what is the best CA rig I could afford to buy' and why.

All the other crazy information out there is really geared towards gamers, who don't really care about RT, that they call 'eye-candy', where as we do.  We don't care about FPS until we are doing a PBR walk-thru.

We now should care less about the CPU and more about the communication pathways between the CPU+GPU+RAM+M.2 NVME and the MB pathways.

I may be wrong but I think that is what the coders at CA are looking at also.

It is way to easy to overspend on crap we really don't need, like water cooling, or pretty cases with side panels to show off all the RGB lights inside.

Rant done...

[Barton_Brown]

1 hour ago, jtcapa1 said:

It is a little frustrating to read threads like these and see a bunch of comments which focus on parts and pieces instead of systems.

The best advice from a cost perspective is get a good graphics card and us PBR instead of CPU RT.

All the threads and cores of the 13900 series of CPU's are costly overkill for 99% of what we do. Not worth the money in a custom build.

Right now, for CA users, it seems like the money is better spend on a high end graphics card.  Barton, another good test is to launch task manager and just look at what the CPU is doing between the i7 cheap CPU and the i9 overpriced CPU.  Is all that money worth the extra 2 minutes you save? On island time?

John, if one were using the PC strictly for CA business, your cost perspective suggestion seems correct. However, I'm a retired nerd that uses the PC for other stuff besides CA - and I have a personal problem with PBR and the way it creates shadows (or doesn't). Yes, PBR is fast and as Renerabbitt has shown, can produce some stunning results. If I were in business I would settle for PBR, but since I am not, ...  On a more subjective level, the i9 PC is enough faster for most tasks to be noticeable (by me). Did I need to upgrade? At the time I purchased the i9 PC the answer was yes because the i7 PC would not boot. Turns out electronics stuff on Bonaire suffers from the salt air and warm temperatures in a house designed to be cooled by the trade winds. While waiting for the i9 machine, I determined that the i7 machine needed a new graphics card (the third one to date). The new card brought the PC back to life but the i9 machine had already shipped by then. So now I have a backup PC  .

 

For me, the Nvidia 4070 TI GFX card is good enough, and certainly not a slacker card. It rips right along on video editing tasks as well.

 

I use a windows gadget called 'cpu usage' that shows the activity level of all cpus/threads and their associated temperatures. On the i7 machine I can have all 16 threads/cores pretty well maxed out and the CPU temps stay in a reasonable range. On the i9, when more than 10 cpus/thread are running, I get critical temp warnings on a couple of the CPUS. But, as I said, 8 I9  cores are still faster than 15 i7 cores. Time to tweak CyberPower again as they have not responded to my temperature questions.

 

Interestingly, for me, the i7-6900K machine and the i9-13900k machines were almost exactly the same cost - one purchased in 2017 and one purchased in 2023. I haven't considered either one of them to be 'cheap'  .

[Barton_Brown]

21 minutes ago, jtcapa1 said:

I want to rant a bit here, so forgive me.

...

We now should care less about the CPU and more about the communication pathways between the CPU+GPU+RAM+M.2 NVME and the MB pathways.

I may be wrong but I think that is what the coders at CA are looking at also.

It is way to easy to overspend on crap we really don't need, like water cooling, or pretty cases with side panels to show off all the RGB lights inside.

Rant done...

Don't disagree with you here. That is why I focused on the fastest RAM+M.2 NVME I could get. 

I will disagree slightly on 'the other crap'. Water cooling, in my situation, has been very helpful (non-AC house in the tropics). I have had both air and water cooled solutions and won't go back to air-only. I did a slight upgrade on the case, not to see the lights, but to get an aluminum anodized solution that would not rust out as some previous cases have.

[Barton_Brown]

2 hours ago, Renerabbitt said:

Sooooo I would agree with you, until I got a machine with PCI 4 and DDR5, and now I will never use my i9 based machine again because it was on PCI3 and DDR4. The difference feels like a LOT

Yup. PCI4 and DDR5 make for a nice speed boost!  

[jtcapa1]

On 4/21/2023 at 3:38 PM, Barton_Brown said:

Don't disagree with you here. That is why I focused on the fastest RAM+M.2 NVME I could get. 

I will disagree slightly on 'the other crap'. Water cooling, in my situation, has been very helpful (non-AC house in the tropics). I have had both air and water cooled solutions and won't go back to air-only. I did a slight upgrade on the case, not to see the lights, but to get an aluminum anodized solution that would not rust out as some previous cases have.

I would not want to work in the tropics for the reasons your explaining.  I made the mistake of taking my work laptop to Hawaii once, never thinking about those nice cool trade windows blowing into our ocean front condo.  My laptop died after about 3 days!.  Local repair shop smirked and said he see's this all the time.  So water cool everything sounds smart when you live in paradise.