What are the minimum hardware requirements for running big models smoothly?

I love the use of big models and minimum in the same sentence. Sorry I couldn’t resist. :joy:

I’ll try to be as non-technical as I can, though my wife tells me that even when I try to be plain I still spew “engineer talk” :wink: I can only hope this makes sense and that the other nerds out there will forgive any over-simplification.

In the old days (not that long ago!) a CPU chip contained a single processor providing all the hardware to perform any sort of calculation. The term “multi-processor” means a computer that has more than one CPU. Most “supercomputers” are multi-processor. The first-generation Mac Pros had two processors.

But as the size of the circuitry was shrunk, it became possible to fit more than one suite of processing hardware on a single CPU chip. This saves both space and power compared to a multi-processor. Some of the circuitry is shared between these suites, so each distinct, self-contained part to support calculation came to be called a “core”. Today a single CPU chip will typically have 4, 6, 8, or even more cores. An 8-core CPU has almost the same capabilities as a multi-processor with 8 separate single-core CPUs, but in a smaller more efficient package.

Every current generation Mac uses a single CPU with multiple cores.

The term “thread” refers to an ordered sequence of processing steps to be executed. It is a programming concept at heart, whereas a core is a hardware concept. Its relationship to “core” is that at the simplest level a thread is the workload that can be assigned to a single core at a time. In modern CPUs that’s an oversimplification, as engineers have invented incredibly sophisticated means to share a core across more than one thread - so called “hyper threading” - to make one core do effectively the work of two.

Threads are relevant to SketchUp because to date nobody has managed to break the heart of a 3D modeling program into threads that can run in parallel. It’s performance is therefore limited most of the time by the single-core speed of the CPU. The number of cores may matter for other purposes such as renderers, but not for SketchUp. That speed depends on both the clock speed of the CPU and the intrinsic speed of the CPU hardware. To compare two Macs you have to do some research, for example to find out whether the single-core performance of a 2.6Ghz i5 is better or worse than the single-core performance of a 2.3Ghz i7. Sometimes the difference is less or other than the raw clock speed might lead you to expect.


Steve, I do like to have technical stuff explained, so thank you for taking the time.

However, for a non-nerd, I am wondering how you make use of the information with regard to running SU. I suspect that multiple cores, threads, or processors, will make no difference to SU but could well make a difference to a third part renderer (which I don’t use).

The advice in the Help pages seems to suggest that a processor faster than 2.1Ghz might be better but it might equally be that anything faster will work but make no difference. Similarly, it suggests that more than 1GB of video memory could also improve things. The lesson learnt by @pbacot here is salutary. He tried to upgrade but found it made no difference. I bet he wishes he had known in advance that that would be the case.

To demonstrate just how difficult it can be to get at what you need to know, I believe the Mac Mini sports an Intel UHD Graphics 630 video card. The Apple site doesn’t say anything about video memory. I think (but am not sure) that that card has no on board memory at all and uses the CPU. If that is right, it would presumably be a big mistake to try running SU on it. It’s a jungle out there!

You’ll find the Intel® website provides a plain language description of product features.
Simply click on the info ? buttons.

Here’s the tale of three CPUs

• Core2 Duo E8400 ----- 2 Cores … 1 processing thread per core — 2 Threads
• Core2 Quad Q9650 — 4 Cores … 1 processing thread per core — 4 Threads
• Core i7-6700K ---------- 4 Cores … 2 processing threads per core – 8 Threads*

*Hyper-Threading delivers two processing threads per physical core.

Notice the nearly identical Single Thread Performance of the Core2 Duo and Core2 Quad
Both run SU about the same, despite the Quad’s overall performance of nearly twice the Duo’s

The much higher Single Thread Performance of the Core i7-6700K is the result of higher clockspeed
and modern internal architecture.

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Thanks for all that.

Are those processors the ones that the current iMac use? This is what is on offer at the Apple Store:


These days, a processor slower than 2.1Ghz is a low-end model most likely in a computer that will also have cut other corners to hold the price down and will therefore be a poor performer in general. I think the Help pages are trying to steer SketchUp users away from such models, but I don’t think they meant to imply that a faster clock speed won’t yield better performance.

The difficulty for non-techies is that there are a lot of factors that the engineers can trade off when designing a computer, and comparisons based on specs such as CPU clock speed can be misleading. For example, the 2.6Ghz i7-9750H used in the base model of the new 16" MBP benchmarks as 3% slower than the 2.3Ghz i9 used in the next configuration step up. But that’s also so small a difference that you are not likely to notice it during use. The greater difference is that the i7 is a 6-core version whereas the i9 is an 8-core version - which as we have discussed does not matter to SketchUp.

My general advice would be that unless your old computer is at least 3 years old you are not likely to notice much difference when upgrading to a new one of the same kind. If you have a top-end iMac or MBP, “upgrading” to the newest one is likely to disappoint you. The changes these days are more incremental than radical in the kinds of CPUs used in consumer computers.

This is again a uni-directional recommendation based on the fact that less than 1GB of dedicated graphics memory suggests an older or cheaper graphics system. Somewhat more (e.g. 2-4GB) is almost certain to also involve a more capable graphics processor, but going further is not likely to make much difference for SketchUp. For the same reason, high-end “gamer” graphics do not provide much advantage to SketchUp. It simply doesn’t use the features they add.

So-called “integrated graphics” (which includes all of Intel’s offerings such as the UHD 630 you mention) put the graphic circuitry on the same chip as the CPU and use the same RAM memory as the CPU. They aren’t a graphic card and don’t have RAM of their own. On Windows, these are notorious for issues with OpenGL support in their drivers. Because Apple writes their own drivers, there are usually not issues there. (Aside: contract issues with Apple writing drivers is reportedly one of the reasons Apple parted ways with Nvidia).

Yes indeed!

Wait a beat for a new iMacs

No, those are just ones @Geo chose to illustrate performance comparisons.

I think you are helping me to home in on things. My current machine is late 2012 with a video card that only has 512MB of memory. So I suspect a machine with a faster processor and especially a better video card will make a noticeable difference. I am still veering towards the 3.6 Ghz 8th gen i3 processor with 2GB Radeon Pro 555X video card. Anything above that looks like making little odds.

@josm3’s advice is interesting too.

Indeed it is, Dr. Livingstone.
That’s why it’s important to do your research before spending money.

Apple seems reluctant to state the actual model number of the CPU.
Below are the specs. for what I believe are the i3 and i5 CPUs in the image you shared.

I’d opt for the i5 system for future proofing reasons circled in green.
Of course, it’s easy to spend OPM … other peoples money.

Mac Models

Intel Core i3-8100 @ 3.60GHz

Intel Core i5-8500 @ 3.00GHz

I have been in that situation, about 6 years ago, management did not want to spend any more than necessary. So I bought the minimum required hardware. Six months later the software saw a major major change…wasted $399 and change. The laptop did not have the required port needed for the new software plus using an adapter was not recognized by the software. New laptop time…If I had spent another $75, the required port would have been on board.

Your advice has really helped Geo - thank you.

So this is what I’m going to present to my colleagues as a step by step guide to checking single thread performance before buying a laptop:

  1. Identify the laptops processor:

  2. Go to www.cpubenchmark.net and enter the name of the processor in the search box:

  3. Click on the relevant search result:

  4. And scroll down to find the Single Thread Rating:

  5. You really need the single thread rating to be 2000. If it is - the laptop should work well for SketchUp.

Do you think 2000 is the a sensible minimum by the way - given that the models we use have approx 2,000,000 edges and 900,000 faces?

What about RAM and model size. Is there any reason to believe 16 or 32 mb makes a difference over 8 when it comes to large models?

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You tempt me strangely.

That might depend on what other processes are using the ram. If the processes are utilizing all the ram then the swap file is used. this slows the activity down because the swap file is on the disk drive. This would be less noticeable with an ssd or M.2 storage.

It takes an extremely complex SketchUp model to need more than a few GB of memory. But as @RLGL pointed out, all the other processes in the computer are competing for the same memory. It is typical for the OS itself (including all the helper processes it launches) to use up something near 2GB. Leave a browser and email reader alive and they may eat another GB. Add a photo editor, a renderer, or other heavyweight, and it is easy to have only a few GB free even before you launch SketchUp. So, having just 8GB is living on the edge. I speak from experience, having just 8GB in my MBP Retina. I often struggle to assist with a large model posted on the forum because it drives my Mac into swap. If it were possible (on a MBP it is not, everything is soldered down), this is the first thing about my computer I would upgrade. 16GB is probably enough for almost everyone today, but if you are going to keep the computer for more than a couple of years I’d opt for 32GB, as the memory footprint of everything has been relentlessly growing.


I have the same era machine despite having already bought a mid-2014 machine a while back to move to. Finally getting that done is one new year’s resolution. Still tempted by deals at B&H on this, this and this; all with 32GB of RAM. Also, being mid 2018, you can hang back on Mojave and keep running older 32 bit apps.

I read this entire thread not realizing at first that it was more germane to me that I thought. I was thinking about upgrading my MBP 2014 with an 2.5 GHz Quad-Core Intel Core i7, for their latest and greatest. And then when I read that SU only uses a single core and a single thread, the whole thing became moot. Investing almost $3,000 for a barely recognizable performance increase doesn’t seem very wise. I would only be upgrading to get better SU performance since my MBP does every thing else very nicely. I have worn some of the black plastic off on some of the more used keys, but that doesn’t mean a thing. With a solid state hard drive, the computer doesn’t seem to degrade like older mechanical drives do.

That isn’t a bad processor at all! The only thing is that the new model has a professor significantly faster, and the speed difference would definitely be more than “barely noticeable.” I made the same upgrade recently and performance upgrade was significant with the 3.5-4.5ghz processors over the 2.5.

What machine is giving you that clockspeed? On a Mac?