Does adding cpu cores really make much difference if not rendering with them?

[Paul King]

I have a PC with an old 4 core 8 thread i7 4790K CPU, 32 GB RAM, M.2 drive SSD, and GTX980Ti GPUs.

I have been considering an upgrade to something that can handle more CPU threads, in the hope that ArchiCAD23/24 will become more responsive on complex hi poly count , multiple hotlinks etc projects.

I am a freelancer and generally have to work with projects as I find them - model structure and efficiency are often out of my hands, and I tend to have to follow whatever 'lowest common denominator' office standards are already in play when I am brought in.

I am also at the mercy of whatever imported structural and services IFC models are produced when attempting to coordinate (generally no fancy BIMcloud services on tap - just old fashioned manual IFC file exchanges via DropBox). Switching one or two of these on I find can bring any ArchiCAD session to its knees, particularly if the engineer responsible has not been very good with separating things into useful layers, meaning every bolt has to be shown when beams are switched on, and when everything appears on a single story etc.

Obviously am also impacted by whatever remote Bimserver and VPN folder structures setup I need to dial in to but appreciate more CPU cores won't help with this one.

Sometimes I need to have more than one such project open at the same time. As well as maybe a session or two for hotlinked modules being edited, the normal Email, PDF viewer and browser windows open (generally not too demanding in themselves)

Other than model efficiency, the only variable I do have much control over is my own hardware.

I don't use CPU rendering at all - all GPU based.

All things being equal, am I likely to notice much day to day benefit while wrangling large cumbersome models by switching to something with 10-12 CPU cores? Jumping between views, loading 3D geometry into GPU etc. Would more than 12 make a lot of difference? (where do diminishing returns kick in)

Any benefit at all in moving to a PCIe 4 bus, with all that data needing to be shunted between harddrive and GPU?

Any tips most welcome.

[Paul King]

Thanks for the suggestions

Unfortunately I don't have access to a high CPU core machine to test with ArchiCAD - this is why I was hoping someone on here might have tried it.

Sadly I often don't have a lot of say over what is included or excluded from models I am assigned to work on as a freelancer (I am usually bought in when the model and documentation is already quite far along, but the practice recognizes they need help), so I can't always rely on good model optimisation techniques or structure to solve my problems.

Consistently it is editing and refreshing while trace reference is on (it needs to be on a lot, because a lot of what I end up doing is cleaning up discrepancies from one story to another) , or with sections and elevations in large complex models with lots of SEO and/or IFC models referenced in etc. or editing in 3D where elements I need to snap to are very large, or there needs to be a lot of potential snap candidates visible at same time etc that I notice lagging.

Am on PC, with always up to date OS

Yes, I am intrigued about the new AMD hardware coming up, and given shortages of Nvidia rx3080 GPU anyway, it may not be crazy to wait longer.

[Erwin Edel]

With trace and reference it always speeds things up if you trace from the Project Map rather than the View Map. Even if all the view settings are the same with your active view, I think. Certainly so if they are different.

I think SEO does benefit from raw CPU power, not sure if it is optimised for multiple cores. You can maybe see that with Task Manager in your current setup.

Sloppy SEO usage can really bring things to a crawl. Like selecting all the walls and using a roof as an operator, regardless if they walls need to be trimmed by that roof or not.

[Paul King]

Erwin wrote:
With trace and reference it always speeds things up if you trace from the Project Map rather than the View Map. Even if all the view settings are the same with your active view, I think. Certainly so if they are different.

I think SEO does benefit from raw CPU power, not sure if it is optimised for multiple cores. You can maybe see that with Task Manager in your current setup.

Sloppy SEO usage can really bring things to a crawl. Like selecting all the walls and using a roof as an operator, regardless if they walls need to be trimmed by that roof or not.

Thanks - some great tips there! Esp. using project map rather than view map for tracing - will give it a try.
Have not been able to discern the extent to which core share the load for any given task unfortunately.

You also just suggested a very useful wish for Graphisoft - filter seo selections for actual contact either before or after the operation (eg clean them up in the background), discarding non connected objects from recorded operator and target selection sets.

[Barry Kelly]

Paul,
Have you read this in the HelpCenter?


https://helpcenter.graphisoft.com/knowledgebase/25850/


My take on it is more cores are only good if you have sufficient RAM for each of those cores.
And there is a diminishing return when increasing the number of cores, but it seems like it is difficult to quantify it, otherwise I am sure they would have.


Barry.

[Paul King]

Thanks Barry - no I had not seen that article - very helpful.

Sound like the takeaway is yes ArchiCAD will use more than 4 cores if it can get them, even outside of cpu rendering, but for anything but rendering the marginal gains per core diminish a lot with every added core, such that moving from 4 to 8 is not going to have the impact of moving from 2 to 4.

Yes I see the article also seems to bear out what you are saying about having enough RAM per core.

Sounds to me like an upgrade from my current 4 core to an 8 core would be beneficial, as much as anything due to the increased single core performance more modern cpus have, and because 8 is the current default number of cores in a new workstation cpu anyway, but that any more cores than the current 'sweet spot' unlikely to pay for themselves given the steep price jump thereafter.

On that basis Intel is currently looking a bit better than AMD, based on single core performance of their respective 8 core cpus, at any given price level. May all change in a couple of months.

[Nader Belal]

@Paul King

You can even go with 12 cores with Ryzen ....

Anyway, if you're going to AMD, make sure that you check Ram specs, because the RAM velocity have a greater impact on AMD than on Intel.

[Lingwisyer]

Though if you start looking at memory speeds, you might realise that higher is not always faster due to latency increases...

[Paul King]

OK, I can now answer my own question.

I upgraded from 6 year old 4 cores i7490K to a fresh new box with 19 10900K (10 cores, fastest single core speed in retail market, at least this month), 32 GB DDR4 Ram, ITB NVIe SSD, RTX 3080 GPU etc.

Short answer is, yes there is definitely some improvement, but far less than hoped, much of the time. Certainly things are a bit more snappy in 3D, and when selecting an item from a complex scene etc, but subjectively I would rate the upgrade, between CPU anf GPU, as giving maybe a 30% 'experience'/frustration level improvement overall in my current large teamwork project .
Still quite slow working with trace reference on.

Am still also seeing about as much lag during any teamwork operation, despite the BIMserver just having been moved to a new dedicated machine + upgraded from HDD to SSD drives (it had been doubling as a file server apparently!) - and while far less crashing is now occurring now, speed not actually much changed during any teamwork operations.

I don't think this is a straightforward network issue - every time I click Send/Receive- there is a several minutes delay while a steady 0.1MB/s network activity is maintained before, during and after the send and receive, despite both BIM server PC and my PC being on 200MB/s fiber connection in same city. No surges to speak of in CPU or RAM utilization at my end during this process. Data is being exchanged at a trickle in other words, far from saturating network or system capacity.

Am guessing any bottleneck must be with the BIM server conducting some CPU intensive task at other end, maybe scanning database for differences and implications based on my 20 or 30 changes (which in themselves probably don't entail much data)?

This lag remains frustratingly true even late at night with no other users connected/potentially competing for server resources and bandwidth.

[Erwin Edel]

Only tip I can offer is a bit lame perhaps, but: don't use send and receive too often.

Sometimes re-uploading the teamwork file speeds things up and gets rid of the 'bloat' of it, I think.

It's been a while since I've done a teamwork project.

Thanks for the feedback though. Do you feel like schedules have gotten any faster? These are our biggest bottleneck at the moment and I think most of that is done on a single core (if I look at CPU activity).

[Paul King]

I could not say what impact the upgrade has had on scheduling - not a feature very extensively used in my part of the world (too much legal liability, depending what you are scheduling).

In theory even single core operations should show some improvement - maybe around 20-25% from i7 4790k to i9 10900K, though any multi core operations should benefit far more. I am not so far noticing many (or any) multi core operations in ArchiCAD, though I know they exist.

I would be happy to benchmark schedule generation time if you wan to send a test file.