[Klaus M.]

Hi

Please can you help me to suggest what can be better or what is wrong with this configuration, is this low end, medim or high end conifugration?



HP Z840
2x Intel 12 cores, 3.2GHz
256 RAM DDR4 (8x32 or 16x16?)
512SSD + 3TB HDD

Which graphic card will fit this configuration,what will happend if GB is to low?
And does all card support all CFD, CAD softwares,do I need which softwares I will use?

[ErikAdr]

Originally Posted by Klaus M.

Hi

Please can you help me to suggest what can be better or what is wrong with this configuration, is this low end, medim or high end conifugration?

budget 3000euro

HP Z840
2x Intel E5-2687W v4, 12 cores, 3.0GHz
256 RAM DDR4 (8x32 or 16x16?)
512SSD + 3TB HDD

Which graphic card will fit this configuration,what will happend if GB is to low?
And does all card support all CFD, CAD softwares,do I need which softwares I will use?

For cfd memory bandwidth is very important. The cpu you are looking at got a maximum memory bandwidth of 51.2 GB/s which was fine 10 years ago when the cpu was introduced. Today there are better options. Within the budget it is posible to buy a system with at least two alder lake cpus i.e. i7-12700 combined with DDR5 memory. With DDR5 @ 6000 the memory bandwidth is 96 GB/s for each cpu. DDR5 memory got ECC on the DIMM, but if EEC is very important all the way to the cpu you should find a motherboard with a W860 chipset. Supermicro has such a board named X13SAE. Though I have not seen it for sale anywhere yet.

[flotus1]

Again, I urge you to skim through the pinned thread here: General recommendations for CFD hardware [WIP]

We need as many answers as possible to the questions in chapter 0 in order to make useful recommendations. If some of the questions are irrelevant to your situation, just leave them blank. If you don't know the answer to some of the questions, let us know.
Your questions regarding graphics cards are already covered in chapter 3. If you need clarification on something particular, just ask.

Just to illustrate what happens if we don't have the information necessary to help you pick suitable hardware: Intels new Alder Lake CPUs are without a doubt the best desktop CPUs to date. But they can only handle a maximum of 128GB or RAM currently, and definitely not at DDR5-6000. And my general feeling so far is that you don't want to deal with the added complexity of building your own cluster from several PCs.

[Klaus M.]

Originally Posted by flotus1

Again, I urge you to skim through the pinned thread here: General recommendations for CFD hardware [WIP]

We need as many answers as possible to the questions in chapter 0 in order to make useful recommendations. If some of the questions are irrelevant to your situation, just leave them blank. If you don't know the answer to some of the questions, let us know.
Your questions regarding graphics cards are already covered in chapter 3. If you need clarification on something particular, just ask.

Just to illustrate what happens if we don't have the information necessary to help you pick suitable hardware: Intels new Alder Lake CPUs are without a doubt the best desktop CPUs to date. But they can only handle a maximum of 128GB or RAM currently, and definitely not at DDR5-6000. And my general feeling so far is that you don't want to deal with the added complexity of building your own cluster from several PCs.

I think answer is indeed very simple, just need to write best components for given money...

[Klaus M.]

Originally Posted by flotus1

We need as many answers as possible to the questions in chapter 0 in order to make useful recommendations.

Which software do you intend to use?
Fluent, openfoam,cfx, catia,office,davinci,autocad,photoshop... I am not playing video games at all

Are you limited by license constraints? I.e. does your software license only allow you to run on N threads?
dont understand..

What type of simulations do you want to run? And what's the maximum cell count?
simulation of racing cars,boat, aircrafts..dont know what is cell count

If there is a budget, how high is it?
3000€

What kind of setting are you in? Hobbyist? Student? Academic research? Engineer?
beginner but would like to learn it on engineering level doing real complex stuff, not only simple objects..

Where can you source your new computer? Buying a complete package from a large OEM? Assemble it yourself from parts? Are used parts an option?
refabrish parts, components that you tell me I can order to my seller

Which part of the world are you from? It's cool if you don't want to tell, but since prices and availability vary depending on the region, this can sometimes be relevant. Particularly if it's not North America or Europe.
EU

Anything else that people should know to help you better?
-

One of my question is better to assemble work station or "gaming PC" and why?
Maybe works station is not correct decision...?

[flotus1]

Originally Posted by Klaus M.

I think answer is indeed very simple, just need to write best components for given money...

See, it's not that easy.
If someone mainly runs Fluent and has a licence for 8 threads, they need the fastest possible PC with 8 cores.
Someone else might be running open source software without licensing constraints, and the "best" workstation for the same budget might have more, but slower cores.
Or maybe there is a requirement for lots of memory. That disqualifies some of the mainstream platforms, because they only support 128GB maximum.
Or the budget is fixed, but the PC has to be sourced new off the shelf from a large OEM: now the budget for the hardware itself is significantly reduced.

Are you limited by license constraints? I.e. does your software license only allow you to run on N threads?
dont understand..

Fluent needs an expensive license to run. The base license allows you to run simulations with I think 8 threads maximum. You can buy additional licenses to run more threads. Annual license fees can be higher than the price of the hardware itself. Hence the ideal workstation for these commercial solvers looks different than one tailored towards solvers without license fees.

Where can you source your new computer? Buying a complete package from a large OEM? Assemble it yourself from parts? Are used parts an option?
refabrish parts, components that you tell me I can order to my seller

I interpret that as: you don't want to build the thing yourself from parts, but instead want to buy a refurbished workstation. You already mentioned HP Z840 in some other post.
That's a pretty good starting point. I would recommend a dual-CPU setup, with Xeon E5 26xx CPUs from either the 3rd ("v3") or 4th("v3") generation, with 10-12 cores each.
Any graphics card like a Quadro M4000, K5200 or upwards is fine. Ideally, you want 8GB of VRAM.

All of this is assuming you need more than 128GB of RAM. Because if you don't, the suggestion from ErikAdr is very compelling. Since Alder Lake are the fastest single-core CPUs to date, they will be significantly faster for most things pre- and post-processing. Which is where you probably spend most of the time while learning how to use various software packages.
Don't be mistaken though: if your CFD simulation doesn't fit into physical memory, it doesn't just run "a little slower". Even the fastest SSDs are orders of magnitude slower than system memory, which will translate to significantly lower solver performance. And quickly eat the write endurance of consumer-grade SSDs. Can't recommend.

Concerning the question about graphics cards that is now deleted:
Why do I recommend not over-spending on graphics cards, if lack of VRAM can prohibit you from doing post-processing on larger meshes?
I can do post-processing of meshes with 400 million cells in Paraview just fine on my AMD RX570 8GB. I just have to pay attention on what I put on screen. It's a limitation you can usually work around, if you hit it at all.

One of my question is better to assemble work station or "gaming PC" and why?
Maybe works station is not correct decision...?

Yes, this brings us back to how much RAM you want, and whether you want to upgrade it later. And where you want to put your focus: faster pre- and post-processing, or faster solver times. That is your decision.

[Klaus M.]

Originally Posted by flotus1

If someone mainly runs Fluent and has a licence for 8 threads, they need the fastest possible PC with 8 cores.

Yes, this brings us back to how much RAM you want, and whether you want to upgrade it later. And where you want to put your focus: faster pre- and post-processing, or faster solver times. That is your decision.

Thanks for help.

"Don't be mistaken though: if your CFD simulation doesn't fit into physical memory, it doesn't just run "a little slower"

Physical memory you mean on RAM? If not enough what happend, program stop, softwear cant do job?

Where I can see how much threads my software has and what are threads?

From your answer I see that gaming Pc doing some process faster then w. station. I dont know what is pre and post processing and solver time, but I would be nice that computer solve task in less time/days.
I target 256GB..

So if gaming Pc is option then other components I must look at?
It seems @Ericadr suggest gaming components ,he say my CPU is too old / slow and for this money I can buy something better?

[flotus1]

Can you explain me what is threads?
8 threads mean you can simulate 8 task in same time?

In this context, 8 threads means you can run a single simulation, utilizing 8 CPU cores.
Commercial software like Fluent does not allow you to split these up arbitrarily. I.e, you can't opt to run 2 simulations on 4 cores each instead.

From your answer I see that gaming Pc doing some process faster then w. station. I dont know what is pre and post processing and solver time, but I would be nice that computer solve task in less time/days.
I target 256GB..

Pre-processing: everything that happens before a simulation. Geometry generation and cleanup, mesh generation, assigning boundary conditions and interfaces etc.
These tasks are often single-threaded or not very well parallelized. Which means that a CPU with fewer, but faster cores (like a modern desktop CPU) is faster. And let's not forget that you often sit there and wait for these tasks to finish, while you can just run a large simulation overnight.
Solving: well...solving the simulation. Here "server" or "workstation" CPUs with more cores, and enough memory bandwidth to match, reign supreme. Provided we are not limited to a low core count from licenses.
Post-processing: everything that happens after the simulation was run. generating colorful images to visualize the simulation results, using slices, iso-surfaces and the likes. Similar computing requirements as the pre-processing stage.

So if gaming Pc is option then other components I must look at?
I seems @Ericadr suggest gaming components ,he say my CPU is too old / slow?

The comparison made in post#2 is a little flawed. What we really compare are two CPUs with 51.2 GB/s EACH. Memory bandwidth can be added together for dual-CPU setups, which brings us to 102.4GB/s.
And due to the infancy of Alder Lake and DDR5 itself, you can't just run 128GB at DDR5-6000 speeds. At least not yet. So the 96GB/s figure is a bit optimistic.
Long story short: the PC in your initial post will be slightly faster than a single alder Lake CPU for the solver phase. While supporting much more and much cheaper memory.

[Klaus M.]

Originally Posted by flotus1

In this context, 8 threads means you can run a single simulation, utilizing 8 CPU cores.
Commercial software like Fluent does not allow you to split these up arbitrarily. I.e, you can't opt to run 2 simulations on 4 cores each instead.

How can I see how much threads my sofware has?

Originally Posted by flotus1

Long story short: the PC in your initial post will be slightly faster than a single alder Lake CPU for the solver phase. While supporting much more and much cheaper memory.

So maybe is better option to stick with w.stations?

Originally Posted by flotus1

Don't be mistaken though: if your CFD simulation doesn't fit into physical memory, it doesn't just run "a little slower"

Physical memory you mean on RAM? If not enough what happend, program stop, softwear cant do job?

Solving or pre-processing is part when you leave your pc and go to sleep to do the work?

[naffrancois]

Sorry but I have to ask, do you have experience with cfd, fluid mechanics or numerical analysis ?

Softwares where you "scan" a complex geometry painlessly and wait for the results just does not exist. Setting up a simulation, and above all, getting useful results require many skills and a lot of work.

[flotus1]

How can I see how much threads my sofware has?

Among the programs you mentioned, only Fluent and CFX come with limited licenses. If you bought the base version, and nothing else, I think the current limit is 8 threads.
If you are using the free student version, I think the limit is 4, but that may be outdated. But you are further limited to small mesh sizes. around 512k nodes if I recall correctly.

So maybe is better option to stick with w.stations?

With your preference for 256GB or RAM, there is no way around that. You can not put more than 128GB on current desktop CPUs.

Physical memory you mean on RAM? If not enough what happend, program stop, softwear cant do job?

Yes, physical memory is the RAM, i.e. the sticks of memory you put into the motherboard.
Operating systems extend that to virtual memory. The part that exceeds physical memory occupies an SSD or hard drive. You can configure that to be as large as you want, but you will be limited by the speed of that drive.
For perspective let's just compare sequential speeds: CPUs have in the order of 50-200GB/s memory bandwidth. Even PCIe 4.0 NVMe SSDs only reach 7GB/s. Comparing latency, it doesn't get any more favorable.
If you run out of physical memory, performance tanks. If you run out of virtual memory, the program crashes.

Solving or pre-processing is part when you leave your pc and go to sleep to do the work?

It really depends on the size of the project you are working on. Most parts of pre-processing should be rather snappy. But if you have some seriously complicated geometry with lots of parts, even some geometry cleanup operations can take longer than a coffee lasts. And meshing for a model with more than 100 million cells can indeed be a task that needs to be run overnight. Same for solving a model with this many cells.

Originally Posted by naffrancois

Sorry but I have to ask, do you have experience with cfd, fluid mechanics or numerical analysis ?
Softwares where you "scan" a complex geometry painlessly and wait for the results just does not exist. Setting up a simulation, and above all, getting useful results require many skills and a lot of work.

I am inclined to agree with that sentiment.
Maybe OP should first dip their toes into the water with the hardware that is used to write these posts. It would certainly help to make an informed decision later.

[Klaus M.]

Originally Posted by flotus1

I interpret that as: you don't want to build the thing yourself from parts, but instead want to buy a refurbished workstation. You already mentioned HP Z840 in some other post.

My seller tell me parts are "used" with 1 year warrenty.
Hmm is this OK or must be OEM refabrish, is it safe to buy so expensive and old equpiment if they are used ?

Originally Posted by flotus1

For perspective let's just compare sequential speeds: CPUs have in the order of 50-200GB/s memory bandwidth. Even PCIe 4.0 NVMe SSDs only reach 7GB/s.

Originally Posted by flotus1

If you run out of physical memory, performance tanks. If you run out of virtual memory, the program crashes.

million of cells ,density of grid determine how much RAM do I need ?

Originally Posted by naffrancois

Sorry but I have to ask, do you have experience with cfd, fluid mechanics or numerical analysis ?

Softwares where you "scan" a complex geometry painlessly and wait for the results just does not exist. Setting up a simulation, and above all, getting useful results require many skills and a lot of work.

Yes I know fludi mechanics but dont have any experinece is software as you can see from my questions..

[flotus1]

Had a long think about this whole situation. Please don't take it the wrong way:

I am having second thoughts about a total beginner buying a 3000€ PC. And me being complicit in that. You don't need that to learn how to use CFD. Start off small, get familiar with the software via tutorials and just doing stuff, see if it's for you. This can be done with pretty much any old computer you can get for 200€ on ebay. If you are not writing from a phone, you probably already have a capable enough PC to get started with learning.
When you are more familiar with some of the concepts thrown around here, you can make a much more informed decision about what you actually need, before throwing a large sum of money at it.

[naffrancois]

Originally Posted by Klaus M.

Yes I know fludi mechanics but dont have any experinece is software as you can see from my questions..

As Alex said, if you have a personal laptop or pc you can already learn a lot before investing that amount of money in a workstation.

When I was a student I compiled a big cfd code on a 10inch notebook, that was enough to do some 2D cases and learned a lot with that.

Number of cells in a simulation directly impacts the amount of RAM you need. A very rough estimate would be 1 million element needs 1 or 2 GB depending on the software and the equations solved. This is something you need to experience yourself in order to know what you will need on the hardware part.

[Vestdam]

Originally Posted by flotus1

Fluent needs an expensive license to run. The base license allows you to run simulations with I think 8 threads maximum.

Just to clarify on this:
Base ANSYS CFD license allows 4 cores maximum.
Buying an additional "HPC" license enables 8 more cores, so 12 maximum. After this, additional HPC licenses enables 32, 128, 512 etc. additional cores.

[Klaus M.]

Originally Posted by flotus1

Had a long think about this whole situation. Please don't take it the wrong way:

I am having second thoughts about a total beginner buying a 3000€ PC. And me being complicit in that. You don't need that to learn how to use CFD. Start off small, get familiar with the software via tutorials and just doing stuff, see if it's for you. This can be done with pretty much any old computer you can get for 200€ on ebay. If you are not writing from a phone, you probably already have a capable enough PC to get started with learning.
When you are more familiar with some of the concepts thrown around here, you can make a much more informed decision about what you actually need, before throwing a large sum of money at it.

I think I will completly give up from cfd...

my laptop to just open windows it take 15mintues so I dont do nothing at that 15 years old shit...

[Klaus M.]

Originally Posted by Vestdam

Just to clarify on this:
Base ANSYS CFD license allows 4 cores maximum.
Buying an additional "HPC" license enables 8 more cores, so 12 maximum. After this, additional HPC licenses enables 32, 128, 512 etc. additional cores.

Hm only 4 cores.

[naffrancois]

Originally Posted by Klaus M.

I think I will completly give up from cfd...

my laptop to just open windows it take 15mintues so I dont do nothing at that 15 years old shit...

What is difference between used parts with warrenty and oem refabrish?
What oem refabrish can do with cpu,ram and other parts, open and instal new diodes inside? I doubt..

I think only can do is to just clean parts from outside dust..

Nobody wants to discourage you from jumping into CFD. But you should be aware that you will have to invest a lot of time and money to get real world applications working. As you begin from scratch, get a second hand laptop that will be useful for you aside of CFD. Learn the basics, run some tutorials with free softwares, learn a bit of linux, get some theoretical courses. Then, you will have a clearer view whether you want to continue or not and invest in a more powerful hadrware

[flotus1]

See, I'm not even sure any more if these questions are genuine, or if I have fallen for a rather elaborate trolling attempt.
Jumping wildly between topics, opening just more and more questions with every single new post, and being super stingy about giving information yourself. Not to mention how we even got here. I'm out, sorry.

[Klaus M.]

Originally Posted by flotus1

This can be done with pretty much any old computer you can get for 200€ on ebay. .

You must be kidding me.

Originally Posted by naffrancois

Nobody wants to discourage you from jumping into CFD.

for the second time I try to configure PC and I am still nowhere, at the beginning.
I am out too.