[veriflow3]

I have a Windows 10 laptop that I use for running CFD models in COMSOL, often with turbulent flow physics. The laptop has the i7-7700K processor (4.2 GHz, 4 cores, 8 threads, 2 memory channels) and 64 GB of RAM (4 x 16GB, 260-pin DDR4 2133).

Due to finer mesh requirements with my geometries and SST turbulent flow models, I have run models up to 10 million degrees of freedom and have on occasion utilized up to 50 GB of RAM on my machine. More typically my models utilize 20-30 GB of RAM.

I have been looking at single-thread benchmarks on PassMark to compare i7-7700K with some of the newer processors out there, but it's unclear to me if upgrading the i7 will produce ground-breaking speed-up, at least for COMSOL.

Would it be a good investment to upgrade to faster RAM, or does that depend on the motherboard used in the laptop? Do I have anything to gain by upgrading the processor and investing in a system like Xeon 6244 or Xeon W-series, compared to my i7-7700K?

Any thoughts welcome and appreciated.

[flotus1]

What you would need to get better performance is more memory bandwidth and more cpu cores.

It might be possible to get faster memory for your laptop. The first thing you should try is whether you can set it to higher frequencies in the bios.
But that will only get you so far, it still remains a dual-channel CPU with 4 cores. There are no faster CPUs you can upgrade to with your laptop.

For a serious upgrade, you have many options. But all of them involve a regular desktop PC.
What that could be depends mostly on how much you would be willing to spend. It starts around 1500$ for a HEDT system and ends at around 10000$ for a dual-socket workstation. Would you be willing to switch to Linux as an operating system? I've read that windows is not ideal for Comsol once you have non-uniform memory access.

[veriflow3]

Thanks a lot for your reply!

Originally Posted by flotus1

What you would need to get better performance is more memory bandwidth and more cpu cores.

I'm glad you pointed me to this -- nice general information there. That was very educational.

Originally Posted by flotus1

It might be possible to get faster memory for your laptop. The first thing you should try is whether you can set it to higher frequencies in the bios.
But that will only get you so far, it still remains a dual-channel CPU with 4 cores. There are no faster CPUs you can upgrade to with your laptop.

For a serious upgrade, you have many options. But all of them involve a regular desktop PC.

What that could be depends mostly on how much you would be willing to spend. It starts around 1500$ for a HEDT system and ends at around 10000$ for a dual-socket workstation. Would you be willing to switch to Linux as an operating system? I've read that windows is not ideal for Comsol once you have non-uniform memory access.

I would generally prefer to stay with Windows because it's convenient for other software I have to use on this machine. However, if the performance benefit with Linux is substantial, I would consider going with Ubuntu or the like. I have used Linux in the past but would really prefer not to go that route.

I don't mind a desktop. I would prefer to stay within the $5K mark, but again if performance gains are substantial beyond that price point, then I would consider a $7K-8K machine.

Some of the systems I looked at include Intel Xeon W-2133 (3.6 GHz, 6-core) with DDR4 2666 MHz ECC RAM or Intel Xeon 6244 (3.6 GHz, 8-core) with DDR4 2933 MHz ECC RAM.

Are these good choices to consider? Are there better choices?

[flotus1]

Xeon (W) are fast CPUs, but they lack in the price/performance department.
With a core-I9 for the same socket on X299, you get substantially more performance for your money. What you want here is 8-10 cores along with the fastest memory you can afford. E.g. DDR4-3600.

That being said, AMD will release a new version of Threadripper very soon. Allegedly, we will see the smaller version with 4 memory channels this year, and a version with 8 memory channels next year. Based on all the information we have so far, they will be the much better alternative compared to Intels I9 lineup, both in terms of performance and prices. So if you can wait at least until the end of this year, I highly recommend doing so.

An interesting alternative that is somewhat available now is AMDs new Epyc 7xx2. It basically is what AMD will release next year under the Threadripper label, but presumably with slightly lower clock speeds.
For example, Epyc 7402P offers 8 memory channels (DDR4-3200) and 24 cores for only ~1400$.

[veriflow3]

Originally Posted by flotus1

Xeon (W) are fast CPUs, but they lack in the price/performance department.
With a core-I9 for the same socket on X299, you get substantially more performance for your money. What you want here is 8-10 cores along with the fastest memory you can afford. E.g. DDR4-3600.

Core i9-9900X - $1,000
Cores: 10
Threads: 20
Processor Base Frequency: 3.50 GHz
Max Turbo Frequency: 4.40 GHz
Cache: 19.25 MB SmartCache
Max Memory Size: 128 GB
Memory Type: DDR4-2666
Max # of Memory Channels: 4
ECC Memory Supported: No

Xeon W-3225 - $1,200
Cores: 8
Threads: 16
Processor Base Frequency: 3.70 GHz
Max Turbo Frequency: 4.30 GHz
Cache: 16.5 MB
Max Memory Size: 1 TB
Memory Types: DDR4-2666
Max # of Memory Channels: 6
ECC Memory Supported: Yes

I like the specs of the W-3225, and the price isn't too bad.

Originally Posted by flotus1

That being said, AMD will release a new version of Threadripper very soon. Allegedly, we will see the smaller version with 4 memory channels this year, and a version with 8 memory channels next year. Based on all the information we have so far, they will be the much better alternative compared to Intels I9 lineup, both in terms of performance and prices. So if you can wait at least until the end of this year, I highly recommend doing so.

An interesting alternative that is somewhat available now is AMDs new Epyc 7xx2. It basically is what AMD will release next year under the Threadripper label, but presumably with slightly lower clock speeds.
For example, Epyc 7402P offers 8 memory channels (DDR4-3200) and 24 cores for only ~1400$.

That's impressive. I considered AMD processors, but I remain partial to Intel offerings. Maybe there's no good reason to remain partial to Intel processors over new AMD offerings. Isn't COMSOL compiled with Intel MKL?

[veriflow3]

Thank you for your advices. :-)

It looks like Intel just released the new generation of Xeon W. For example, W-3225 looks really good, and at just above $1,000 it seems to combine fast clock speed with good memory bandwidth. It looks like a considerable improvement over the current Xeon W-2XXX generation, at least on paper:

# of Cores: 8
# of Threads:16
Processor Base Frequency: 3.70 GHz
Max Turbo Frequency: 4.30 GHz
Cache: 16.5 MB
TDP: 160 W
Max Memory Size: 1 TB
Memory Types: DDR4-2666
Maximum Memory Speed: 2666 MHz
Max # of Memory Channels: 6
ECC Memory Supported: Yes

Seems like an improvement over the latest i9 X-series with 4 memory channels and no support for ECC.

I guess the Xeon Scalable family has even higher memory bandwidth than Xeon W, but I think this is where cost/performance ratio really breaks down. Latest Xeon W with their improvements seem to be a pretty good choice.

I am just not sure about AMD processors for COMSOL. I have never used AMDs before, and right now it appears to be a hot trend, so I see Intel as more of a tried-and-true, reliable solution. Maybe I'm wrong. I don't know. :-)

[flotus1]

so I see Intel as more of a tried-and-true, reliable solution. Maybe I'm wrong. I don't know. :-)

I know it may sometimes seem like I was shilling for AMD. The whole situation would better be discussed in a different off-topic thread.
My summary would be: AMD had some genuinely shitty CPUs for the most part of the current decade. But times have changed. Apart from the absolute low end and absolute high end of the computing spectrum, AMD has a SKU that delivers more performance than Intel at the same price point. And even the high end is about to change.
As long as you don't mind throwing more money at the problem -or getting less no matter the budget- for that peace of mind, there is nothing wrong with choosing Intel. I know how that sounds, but that's just the current state of the CPU landscape.

Here in Europe the Xeon W3225 costs the same as the Epyc 7402p. It has 1/3 of the core count, 6 instead of 8 memory channels and only supports DDR4-2666 instead of 3200. Although I haven't seen any benchmarks for Comsol, I am pretty sure these specs alone translate to significantly higher performance.
And as a side-note: one could definitely squeeze the same level of performance (Xeon that is) out of an 8-core I9 CPU. Investing some of the money saved on the CPU into better memory.

But enough of my incoherent ramblings
To get the most performance out of a Xeon W 3225, make sure to pair it with 6 DIMMs of dual-ranked DDR4-2666 memory. And try to avoid those weird socket 3647 mainboards with 8 DIMM slots. Are you building the system yourself or buying a pre-built? I.e. do you need my 2 cents on other components?

[veriflow3]

Not at all incoherent! :-D

I agree that I should have a closer look at the AMDs and do a bit of research, perhaps consult with COMSOL technical support people on their experience with AMD machines, if any.

In the end, I'd like to make sure that whatever machine I go with will provide a substantial speed-up over my current machine, hopefully at least 50% speed-up, ideally at least 2X speed-up. Is that a reasonable expectation starting from i7-7700K with current market offerings? Maybe I should try AMD.

I would definitely appreciate some recommendations on other parts of the system as well, if you have time. :-)

[flotus1]

I agree, contacting Comsol support on their opinion about newer AMD CPUs could be interesting.
As a side-note: the fact that Intel compilers and/or libraries were used is no indication that the software will run better on Intel CPUs, especially when memory bandwidth is a key factor. I've had no trouble getting decent performance on AMD CPUs despite using Intel compilers.

ideally at least 2X speed-up.

That should be doable with the Xeon system.

Other components... I still don't know if you pick the parts yourself, or if you buy from Dell, HP and the likes. So I won't go too much into detail on the parts you have no control over in a pre-built system.
Graphics card: same story as with the CPU. The software will probably run just fine with a cheaper consumer graphics card. But for that peace of mind of having guaranteed support, you might want to stick to the recommended pro lineup of graphics cards https://www.comsol.com/system-requirements#gpu-req
Anything with 4GB of VRAM or more should be fine.
RAM: I bought a couple of these just a few days ago, they are ridiculously cheap here in europe https://geizhals.eu/samsung-rdimm-32...loc=at&hloc=de
6 of them will give you 192GB total for less than 800€. If you have to dial it down a notch with 16GB DIMMs, remember you want dual-rank RDIMM instead of single-rank. The performance difference can be up to 10%.
SSD: they are cheap these days, no proper workstation should be without at least a 1TB NVMe drive.

[veriflow3]

Sorry, I didn't answer your question earlier: yes, I can build a PC and I would definitely consider building one for this application. However, I've been out of the loop on recent technology so I need a bit of guidance. Thank you for all the information you already provided. :-)

I checked with COMSOL support regarding AMD. They had good reports about AMD processors (probably from customers), but they don't engage in extensive hardware testing themselves, so they could not provide a comparison benchmark versus an Intel processor. They did agree that the price/performance ratio with current AMDs looks good, and they have no reason to discourage their use with their software for any technical reasons.

That definitely puts me more at ease to look at an AMD configuration as well and price one out.