ZBrushCentral

Mac working far too hard?

ZBrush Usage Questions
#1

I’m just starting to play with ZBrush on my Macbook Pro. Having a few issues with heat which I wouldn’t really expect.

System is 2.6gHz Quad Core i7 with 16GB RAM and running an SSD. Seems to be massively qualified to run ZBrush practically in its sleep and is certainly miles more powerful than the PCs many of my work colleagues use for ZBrush without any issues.

Now putting aside the effect of my fans going crazy and temperatures getting up past 100C (which is a worrying thing to do on a computer that cost more than £2000) and getting to the cause… I’m wondering is it normal for a computer this powerful to run all four CPU cores at 100% the instant you start sculpting, even on something at a low res?

I can’t help feeling there’s a problem either with my computer or with the software (or, presumably I’m missing something… which would hardly be something new).

Any thoughts would be appreciated. Been thinking of switching to PC but would rather stay Mac if at all possible…

#2

Other Mac users experimented the same heat problem. I have no explanation for that. I would submit a ticket to Pixologic support as it seems to be a recurrent problem for Mac users lately.
It´s very weird because as you said many users can run Zbrush smoothly with low end Pc.

#3

Thanks, glad to know it’s not me just going mad…

Will submit a ticket and see what they have to say/recommend :slight_smile:

#4

I just picked up an Early 2013 Retina Macbook Pro yesterday, 2.7ghz with 16gb Ram and 512gb SSD. I plan to switch platforms (PC to Mac) with hopes this can effectively replace my PC desktop and also work on the go. But now I need my software to change platforms. Luckily Adobe Creative Cloud and Modo let you install either Mac or PC. It’s a bummer there’s no demo to test ZBrush before doing a swap. There’s always running Windows in Bootcamp or Parallels.

I see you had your Mac license up for a swapping a week before this post. Did you decide to keep the Mac version?

Any luck with the heat issues?

I wonder if anyone has reported improvements after updating Mountain Lion to Mavericks.

#5

Hey there.

Been meaning to post again for the last few days. Thanks for the reminder.

I have heard back from Pixologic and they did solve the heat issue (well, sort of). They suggested I go to settings and switch off multithreading to reduce the number of cores the software is using. I haven’t had a chance to really run the software through it’s paces but doing the same tests as before the cpu maxes out at around 20% load rather than 100% constant and the max temp I’ve been reaching is a little over 80C rather than 103C. So, major improvement.

Technically I’m crippling my computer to do it which suggests that there is something of a problem here but it’s a good workaround and my Mac (like yours) is massively overqualified for the job so even running at 20% CPU load I’ve not seen it struggling at all.

So, a lot better and thus I’m keeping my Mac license. Now I need to find time to properly learn how to sculpt with the software…

Oh, and still running on Mountain Lion here. I’m not updating to Mavericks until it’s gone through an update or two. Usually the sensible option for OS upgrades. From what I’ve heard Mavericks is generally pretty quick so hopefully it’ll be an improvement.

#6

Thanks for posting the workaround you got from Pixologic. And you’re right, with these specs, general use in ZBrush with a single thread should be good, plus those temps look a lot better. Then when you need the power you can turn it back on. That’s usually near the end anyway, where you’ll be using certain features or plug-ins that will be pushing 100% to calculate. Got my fingers crossed that there will be a fix soon.

If you have time, can you report how ZBrush works with the Retina Display? Does it display as expected? For performance in the viewport, have you tried making the document about half the size you need it, then simply zooming the doc? Might help work around that high-res slowing things down.

No problem on the license swap, there are two other people that recently posted ads for swaps too. I just wanted to check with you since you posted before them.

#7

Hey guys, I just got the 2013 MBP retina / Mavericks and ran into the same issues with heat and the fans ramping up even when I am working on a very low res model. I tried lowering the the multithreads to 1 and steps to 8 and it seemed to work out, fans do not ramp up crazily. I’m not sure how this has an impact on higher res models, I plan to load some heavy models to test it out.

Zbrush works great with the Retina. I have it set at Scaled to look like 1680 x 1050 and the UI reads fine to me. 1920 x 1200 might be too small for me. I was concerned about scaling issues too (having not used a retina display in the past) but everything seems to be working out fine. There is some aliasing issues on the model but it is very minor.

#8

So I tried setting the priority on ZB’s process to highest in the terminal and it fixes the fan problem. My fans don’t ramp up crazily when working on low-res models and I am using all 8 threads. I followed the steps in this thread.

http://www.zbrushcentral.com/showthread.php?181692-Is-zBrush-compatible-with-OSX-Mavericks&p=1055528#post1055528

Not sure why this would matter nor how it would affect the fans. Could it be a problem with the mac port of ZBrush and how it handles processes?

#9

Have the same issue here: ZB 4R6, 15" Retina Macbook (Late of 2012).

Disabling multithreading helps somehow but only until i start to do even minor work.

Add

Ok, i’ve receive explanation from Pixologic tech support team (thank them!) which means that we actually have to talk to Apple seriously :stuck_out_tongue:

Thank you for using ZBrush! (Thank you for making it! - me)

This is a situation that is something we have been in contact with Apple about for a couple of software releases now. ZBrush is not the only software to have this issue. What is happening is that your computer is seeing each core as a completely separate processor when ZBrush is running it multi-threading. So for example let’s say your CPU temp is running normally at 100 degrees (just an example number). When ZBrush starts up, if ZBrush is using 4 cores then you computer thinks that you now have 4 separate processors each running at 100 degrees and it adjusts the fan to try to cool off all of them, even though it is only one processor. Bascially, your computer is creating its own overheating situation. By thinking it is hotter than it really is, it kicks up the fans which then DOES increase the overall heat because of the fan going into overdrive. Until Apple helps to come up with a permanent solution reducing the number of threads in the multithreading settings is the only work around.

#10

I’m confused by the statement that the fans on cause a heating issue, that seems backwards and no where as stressful on the system as if all cores were at 100%. Maybe the fans will heat up themselves, but wouldn’t the increase in airflow offset that? I’ve left this laptop rendering with all cores for hours with the fans blowing and survives. So if OSX is just falsely turning the fans on, and if they themselves generate heat, still seems just like a nuisance than a danger to the system. I always disable the threads not really know it the CPUs were actually overheating, which you wouldn’t put the laptop through if you didn’t need to, so it’s nice to know it’s just a fan glitch if I do need the performance in the viewport

#11

Well. I don’t know because i’m not any tech-experienced person. As i start ZBrush temp hits 100+ C (iStats) which is maybe normal for a moment of a start. Fans go to work harder. As fans do their job temp goes below. As temp goes below fans take it easy and temps go up again. The process repeat. With active multithreading it’s when i simply have opened program window. When i do turn multithreading off it may have some break when i don’t do anything - that’s the only way it help.

Temp goes up not when fans goes in overdrive mode but when they do actually take it easy.

Rotors give some additional warm, of course, but forcing air has a way higher cooling effect. So yes it sounds a bit illogical as it’s when against physical process of active cooling. But the part that OS X “thinks” it’s hotter than it’s actually is maybe is real. I’m also thinking the way to contact with Apple for investigation of the issue and some explanations, maybe.

Add

A point mentioned on Apple forums by etresoft

The fans are controlled by hardware sensors. When the CPU starts to work hard and heats up, the fan keeps it from getting too hot. The fan does not cause heat. The fan cools. Whatever miniscule amount of heat that the fan motor itself generates is dissapated by… the fan.

There is only one CPU on your machine. If it has 4 cores, and only one of those cores is working hard and heating up, the CPU still gets hot. The cores are on the CPU. You cannot heat up a single core without heating up a CPU.

In modern OS X software, you cannot really turn multithreading on or off. A well-designed program will spawn many small tasks that will be distributed across all cores according to which ones have capacity. If you have 4 cores and are running something intensive on one core and then start up another program that properly implements multithreading, it will only use the remaining 3 cores.

It sounds like the authors of this program are simply using some 3rd party library ported from Linux or something and they don’t understand it any more than they understand computer architecture. To give them the benefit of the doubt, it may be just the support person that is clueless and is telling people a typical blame-it-on-Apple story. I looked at the web site and it seems like a sophisticated program, or at least it was in 1999. It seems to be using obsolete multithreading logic and completely ignoring modern graphics techniques. Apple can’t fix that.