[Mikhail Tal]

Hello everyone!
I am a Physicist and my interest belongs to numerical MHD with Star CCM+ and some more CFD in Spaceweather Applications. Offtopic I am sometimes recording my little music sessions on cubase.
So here I am with all research I have done and need a recommendation for my next pc build which I will use as a workstation.
Good to know, I have a surface book which I used, but there is now strong limitations for my use cases obviously but is my perfect 15" "Blackboard".

I know you recommend the Epycs due to its high octa-channel memory bandwidth. But I don't like the Motherboards for them because of the lack of IO, Sound Card and the fact that they will be sitting under my desk and not in a Server Rack...
The other solution I think would have ticked all my boxes was to go the Threadripper Pro route. But yesterday my dreams ended as I read about the not talked bottleneck of version 3975wx!!! in it's memory bandwidth of max. 110 GB/s in comparison to round about 160 GB/s for the 3995wx version.
So here I am and I need your help. Will I be okay with a Server Motherboard by making too much smaller complaints? Or is there an other way (Xeon Route maybe or 8 core threadripper with Quad Channel?)?
My Budget is 4000 Euros.
I appreciate your thoughts and answers!!!

Kind regards

Mikhail

[flotus1]

The other solution I think would have ticked all my boxes was to go the Threadripper Pro route. But yesterday my dreams ended as I read about the not talked bottleneck of version 3975wx!!! in it's memory bandwidth of max. 110 GB/s in comparison to round about 160 GB/s for the 3995wx version.

Let me take a guess here: you are getting these numbers from this review: https://www.anandtech.com/show/16805...threadripper/8
While anandtech is generally a good source for in-depth reviews, I think they came up short here.
Aida64 is not exactly the best tool to measure anything other than consumer-grade hardware, but that's besides the point. The main issue here is that they only measured/reported write speed, and failed to put the results into proper context.
Memory write speed is generally less important than read speed. Especially for parallel CFD workloads. That's one of the reasons AMD decided to cut the pipeline width for writes in half, starting with their Zen2 architecture. As a result of this, in order to saturate the full memory bandwidth of 8 memory channels during writes, a Zen2 and Zen3 Epyc CPU needs all 8 CCDs. For reads, only 4 CCDs are enough.
That explains why the 32-core (128MB L3 cache) TR Pro 3975WX falls so far behind its 64-core counterpart in this particular benchmark. It only has 4 CCDs active (hence the 128MB L3 cache) and can only saturate the 8 memory channels for reads, but not for writes.
Long story short: The TR-3975WX is the cheapest Threadripper Pro CPU that I could kind of recommend for CFD workloads, if it has to be a Threadripper Pro. The 64-core part is probably a waste of money.

What I would rather recommend is a Zen3 Epyc CPU. Remember, TR Pro is still on the Zen2 architecture. E.g. 7443p if you want to stay on a single socket.
I wholeheartedly agree with your finding that there are no proper workstation boards for AMD Epyc CPUs. Neither single- nor dual-socket.
If all you are missing from motherboards is connectivity and onboard sound, these can easily be fixed with some cheap PCIe cards.

[Mikhail Tal]

Originally Posted by flotus1

Let me take a guess here: you are getting these numbers from this review: https://www.anandtech.com/show/16805...threadripper/8

Thats absolutely right. I am glad to hear good news from you! Thats beyond my knowledge and I learned something new today. Well, the 3995wx model is out of question already cause I was eyeing the 32 core version from the beginning.
Now I kinda tend to build the threadripper built but I am also kind of interested in the EPYC scenario. For building a pc the second time of my life, what do I need to know building an Epyc Workstation? From all I know you are recommending dual socket, but the 7443p is also an option. If I go dual socket 2x 16 cores would be beneficial, right?
Okay i understand that I can extend the Motherboards functions with the right pcie tools.
For approximetaly 80 million cells, how much ram should I get at which speed?
I read about having the same clock speed as the cpu and 2 gb of ram for each million cells. Is that right?
Would you like to give me little help choosing the right components?

CPU: Threadripper Pro 32 Core/Epyc 7443P or Dual Epyc
Motherboard: Asus WRX80/?
RAM:?
Case: ?
PSU: ?
I thought about getting the corsair 680x for the 2 cabin style. Yeah it might not be the cheapest alternative, but I would expend my budget for some extra fanciness. Would it be compatible with both Motherboards? The WRX80 is an E-ATX. Would it fit in that mentioned case above?
Are the Noctuas the right Choice to cool the CPU´s?
Sorry for asking so much stuff, but I am always curious and patient for taking my time to plan everything so the pc building can act like meditation we all now
Thanks for your informative response flotus1!

[flotus1]

For building a pc the second time of my life, what do I need to know building an Epyc Workstation?

It's no different than building a "regular" PC. Just much more exciting because everything is more expensive
Some things to keep in mind about compatibility:
1) Epyc and Threadripper don't mix, despite using the same socket. So no Epyc CPUs on TR motherboards and vice-versa.
2) For Epyc in particular, only use registered ECC memory. UDIMM is not compatible.

If I go dual socket 2x 16 cores would be beneficial, right?

Two 7313 will be faster than a single TR Pro 3975WX. Don't get blinded by higher frequency for TR CPUs. They are one generation older, and there were some significant improvements between Zen2 and Zen3. And of course, you double shared CPU resources like memory controllers and L3 cache. It will be difficult enough to squeeze dual-socket into a 4000€ budget, so anything more than 2x16 cores is probably out of the question.
About the Epyc 7443p though: it is 900€ cheaper than a 3975WX, and you can get a cheaper board along with it. For just about the same level of performance.

For approximetaly 80 million cells, how much ram should I get at which speed?

I probably wouldn't go lower than 256GB. DDR4-3200 is what you need for any of the CPUs in question. TR Pro boards officially support UDIMM, so there is some potential to get lower timings than is possible with RDIMM. But the memory QVL for this board doesn't list a whole lot of faster memory kits, so your mileage may vary.

I thought about getting the corsair 680x for the 2 cabin style. Yeah it might not be the cheapest alternative, but I would expend my budget for some extra fanciness. Would it be compatible with both Motherboards? The WRX80 is an E-ATX. Would it fit in that mentioned case above?

It probably won't fit, which is a good thing if you asked me
These boards aren't "E-ATX", which isn't a properly defined form factor. They are full-blown SSI-EEB (12"x13"). Here is a starting point for cases that might be large enough: https://geizhals.eu/?cat=gehatx&xf=7...2C+12%22x13%22)
Remember: we still lack the technology to phase air through solid materials like glass or plastic. If a case has three ARGB fans sitting directly behind a glass front panel for that extra bling, it won't cool the components inside very well. And most air coolers for SP3 exhaust air to the top, so you also want a case that exhausts air that way instead of blocking it with another glass panel. For air-cooled workstations with high heat output, It's function over form. Or dealing with a loud PC that slowly roasts its components.

Are the Noctuas the right Choice to cool the CPU´s?

NH-U14S TR4/SP3 is what you want for air cooling a dual-socket workstation. For single-socket, there are alternatives like be quiet Dark Rock Pro 4 TR4.

Power supply also depends on which and how many GPUs you intend to use. For a basic dual-socket system, 750W with two 8-pin EPS connectors is fine.

[Mikhail Tal]

It's no different than building a "regular" PC. Just much more exciting because everything is more expensive
Some things to keep in mind about compatibility:
1) Epyc and Threadripper don't mix, despite using the same socket. So no Epyc CPUs on TR motherboards and vice-versa.
2) For Epyc in particular, only use registered ECC memory. UDIMM is not compatible.


Two 7313 will be faster than a single TR Pro 3975WX. Don't get blinded by higher frequency for TR CPUs. They are one generation older, and there were some significant improvements between Zen2 and Zen3. And of course, you double shared CPU resources like memory controllers and L3 cache. It will be difficult enough to squeeze dual-socket into a 4000€ budget, so anything more than 2x16 cores is probably out of the question.
About the Epyc 7443p though: it is 900€ cheaper than a 3975WX, and you can get a cheaper board along with it. For just about the same level of performance.

Yeah I know that both sockets SP3 and WRX80 are not interchangeable. So my choice is between dual socket Epyc and Threadripper Pro.
If I am correct the Epyc only can be used with Windows Server and not Windows Consumer Level. Will I be able to use Windows on a VM in Linux?
Or another idea. Would it be fine to Remote with my Surface with the new Workstation? Just a few thoughts that I have on my upcoming workflow.

It probably won't fit, which is a good thing if you asked me
These boards aren't "E-ATX", which isn't a properly defined form factor. They are full-blown SSI-EEB (12"x13"). Here is a starting point for cases that might be large enough: https://geizhals.eu/?cat=gehatx&xf=7...2C+12%22x13%22)
Remember: we still lack the technology to phase air through solid materials like glass or plastic. If a case has three ARGB fans sitting directly behind a glass front panel for that extra bling, it won't cool the components inside very well. And most air coolers for SP3 exhaust air to the top, so you also want a case that exhausts air that way instead of blocking it with another glass panel. For air-cooled workstations with high heat output, It's function over form. Or dealing with a loud PC that slowly roasts its components.

Okay, I didn't saw that with the glass panel in front and on the top of the case... The Fractal Designs were used by the Youtuber Wendel in his Threadripper Pro Build. If I am choosing a cube style case, which of those would you recommend me? Or what would your recommendation be?

Another question which comes up is using this build as a remote workstation with my surface book 3. Would I be able to leave the Workstation without a GPU and use my GTX 1660Ti in my Surface for visualization?

[flotus1]

If I am correct the Epyc only can be used with Windows Server and not Windows Consumer Level. Will I be able to use Windows on a VM in Linux?

I didn't have serious issues starting up Windows 10 Pro on my dual Epyc workstation. Didn't test much though, since I'm using Linux anyway.
Of course you can spin up whatever OS you want inside a VM.

Or another idea. Would it be fine to Remote with my Surface with the new Workstation?

Sure, why not.

If I am choosing a cube style case, which of those would you recommend me? Or what would your recommendation be?

I don't have a cube-style case in mind I could recommend. The selection is limited anyway, because with all the wasted space for cube-style cases, most of them are for ATX form factors and smaller. They would be seriously huge like the Thermaltake Level 20 HT, which I can't recommend for air cooling with its rotated layout.
What I can recommend: Phanteks Enthoo Pro (both v1 and v2), Fractal Meshify 2 XL. Or if it has to light up like a Christmas tree: Lian Li O11 Dynamic XL. It might require the optionally available expansion bar for SSI-EEB boards. Though it will probably look hilarious with the green PCBs of a server board and memory, along with Noctuas brown color scheme.

Would I be able to leave the Workstation without a GPU and use my GTX 1660Ti in my Surface for visualization?

Not exactly my area of expertise. But the usual route is the other way around. Not sure if there are viable solutions for what you have in mind.

By the way, AMDs TR 5000 (Zen3, like current-gen Epyc) are rumored for release November this year. How much those rumors are worth, and what a release means for actual availability is a different story entirely.