this post was submitted on 06 Apr 2024
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Hey Lemmy, I need some recommendations for a CPU-intensive slightly mobile rig. I run a lot of engineering simulations and I need a computer that I can move between my home and work on a semi-frequent basis. I'm looking for something more powerful than a laptop and I'll have monitors/peripherals at both locations. Maybe a mini-ITX in an HTPC style case? The sims don't really make use of GPU, so integrated graphics is just fine. They multi-thread a bit, but there are still single-core bottlenecks in the process, so highest single-core performance is probably pretty important. It's also got to handle 128GB of DDR5 and a M.2 PCIe NVMe SSD.

A lot of the faster CPUs seem to need some serious cooling (100W+ TDP!) and I'd rather not have a jet engine roaring constantly since this thing will be sitting right on the desk next to me eating 100% CPU most of the time. Are there small form factor cases that can support water cooling? When Intel says a CPU has a processor base power of 125W, but a Max Turbo Power of 253W, does that imply that the 253W can't be sustained even with enough cooling?

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[–] [email protected] 9 points 8 months ago* (last edited 8 months ago) (1 children)

Be careful on the 128GB of DDR5, portable PC or no. One nasty surprise I had recently when putting together my first machine with DDR5 that I had not expected is that a number of motherboards cannot run 128GB of DDR5 at the memory's rated speed. Not something that was a problem pre-DDR5. Check motherboard memory compatibility lists. It actually matters this time around.

[–] [email protected] 1 points 8 months ago* (last edited 8 months ago) (1 children)

ITX also only has two slots for memory, so you'd need 2x64GB—a pricey prospect, if such a thing even exists, in addition to any inherent stability issues (which you'd absolutely need for computational work).

Edit: clarification

[–] daddybutter 2 points 8 months ago (1 children)

Got curious and looked it up. 2x64GB DDR5 kits exist though it looks like they're all ECC (probably a good thing in OPs use case). The cheapest kits, which are 4800Mhz CL40 sticks, start around $500 after tax.

[–] [email protected] 2 points 8 months ago

$500 on RAM seems OK, good to know it's a bit of a narrow market...

[–] [email protected] 4 points 8 months ago (2 children)

Have you considered leaving a big beefy one at work and accessing it remotely from home?

[–] [email protected] 4 points 8 months ago (1 children)

Yes! I've even tried it, but the issue I ran into was that my Starlink home connection is... spotty (I really need to move dishy up higher to get fewer obstructions). This results in network dropouts every couple of minutes which is suuuuper frustrating when you're doing 3D modeling work. Also, working over a remote connection seemed pretty clunky at times with the 3D model manipulation, def not as smooth as local.

[–] [email protected] 2 points 8 months ago

There are a couple people in my company that work that way and it works for them.

The laptop might be the most portable solution.

You might even consider just buying two PCs and using something to sync the work between them. Modern file sync programs are pretty good. I'd recommend checking to see if your modeling program has an officially supported one first.

[–] [email protected] 1 points 8 months ago (1 children)

This seems like a good option, assuming your work will let you access remotely. It's honestly surprising to me that they'd let you bring your own hardware back and forth and allow it on the network.

[–] [email protected] 1 points 8 months ago

Haha well it's my company, so I can do whatever I want?

[–] Beryl 3 points 8 months ago* (last edited 8 months ago) (2 children)

Yes the 253W can only be sustained with adequate cooling, and even then, the VRMs might become a limiting factor. If you're concerned about heat dissipation, don't go with Intel. They can only match AMD in compute power by throwing ridiculous amounts of Watts at the problem.

For a case that can handle 240mm AIO water-cooling in a small form factor (SFF), you can take a look at the lian-li A4 H2O (~10L), although if you don't have any use for a large GPU, there probably are smaller enclosures you could use.

[–] [email protected] 2 points 8 months ago

There's lots of SFF case options that can accommodate liquid cooling and are portable. Since it will be sans-GPU, any sandwich case could instead be modified to utilize the extra space for a radiator (if it doesn't have that already).

[–] [email protected] 2 points 8 months ago (1 children)

Great website...

Wouldn't a mobo advertise that its VRMs would support sustained 253W as a selling point? It was my understanding that AMD couldn't touch Intel's single-threaded performance. ST performance isn't the be-all-end-all performance metric, but it seems relatively important for my use.

You've got me looking at Threadrippers now and... 350W TDP?!?!?

[–] Beryl 1 points 8 months ago (1 children)

Do Threadrippers beat Intel in single thread ? They are geared for heavily multi threaded applications, not so much single thread. Besides, I'm not sure there are any compact mobos for Threadripper.

[–] [email protected] 2 points 8 months ago* (last edited 8 months ago) (1 children)

Yeah, you're right. Threadrippers are definitely not the right approach here.

I'm seeing relatively the same multithreaded performance from a i9 14900K as a Ryzen 9 7950X and the 14900K has a solidly higher single-threaded performance according to cpubenchmark.net

https://www.cpubenchmark.net/high_end_cpus.html

https://www.cpubenchmark.net/singleThread.html#desktop-thread

[–] Beryl 1 points 8 months ago (1 children)

In passmark intel does indeed beat AMD (albeit at almost twice the needed power), but it's not so clear in other benchmarks, see for example : here or here.

Ultimately, it seems Intel 13900K or 14900K would probably give you a slight advantage, maybe about 5%, but that's only if you can cool it well enough that it doesn't have to throttle to prevent overheating, which might happen really fast if you want to put it in a case that would allow you to cary it around. The heat these cpus dissipate means that if you intend to run them at full throttle for long periods of time, you probably have to use a 360mm or 420 mm watercooling, or 2x240 mm but then you have to build your own loop. That won't fit in most SFF cases.

[–] [email protected] 1 points 8 months ago* (last edited 8 months ago)

Great point, it's not so clear cut of a lead. 14900K wins in price, but I haven't factored in the cost of the mobo that might even out the total cost.

A case like Silverstone Alta G1M would let me fit a 360mm water cooler in there, but the build is starting to get larger and larger :P A lower TDP would need smaller coolers and fit smaller cases like you said.

I can fabricate a handle for it, and I'm considering perhaps smaller cases that I could stuff a 360mm cooler into where a GPU would be. e.g. Mechanic Master C30pro (aside from the glass...). As long as the case can handle a long enough GPU, it would fit a 360mm radiator (~400mm long) and I could bolt it to the side panel and cut some ventilation. Sadly many of the cases out there seem to be tempered glass side panels... can't cut/drill that!

[–] I_Has_A_Hat 3 points 8 months ago (1 children)

I don't have a brand recommendation, but it sounds like what you're looking for is a workstation laptop. They tend to be pricier than regular laptops, but they are designed for engineering type work.

[–] [email protected] 1 points 8 months ago

Yeah, that's kinda the typical approach. I'm hoping I can piece together more performance and less noise for the same price. Kind of a waste of a battery and screen if I'm just going to plug it into a station every time... The comparable laptops do alright but they get damn hot and they cost $5k

[–] [email protected] 2 points 8 months ago* (last edited 8 months ago)

If you have duplicate peripherals and assuming you drive and don't have any stairs or whatnot, what I'd do is a normal size case with a carrying handle. One on top and you carry it like a briefcase, makes it pretty easy. Either by design or by diy.

*Apparently these also exist, somewhere anyway https://www.amazon.com/Premium-Adjustable-Computer-Chassis-Carrying/dp/B000KOGB5E

[–] [email protected] 1 points 7 months ago

For a case? I've had a fantastic time with my Hyte Revolt 3 It's ITX, fits 240 AIOs and water cooling easily and even custom loops if you're careful about part choice.

It comes with a sturdy carrying handle, is easy to build in, and has been rugged enough to through into a (hard shell) carry-on bag and take with me on work trips.

For CPU choice, why Intel over AMD? The AMD chips usually have lower TDPs. In your case, because you're looking for max single core instead of max multi core, you can look at second tier chips like Ryzen 7800 or Intel 14700 which usually pair 95% of the core speed with 70% of the heat and 70% of the cores. Undervolting is also an option, and AMD makes that easier.

As far as CPU wattage and heat, there's always some kind of tradeoff. It'll be audible but with the right cooler and CPU you can keep it manageable

[–] Nikls94 1 points 8 months ago (1 children)

I was about to suggest the top of the line Apple Mac M3 Ultra and a Thunderbolt to NVME dongle, but it’s only got 48 GB of combined RAM and on top of that if your softwares don’t run on macOS It’ll be a waste of time and money.

What about the MNT reform?

https://shop.mntre.com/products/mnt-reform

You could play around and find out if this will satisfy your needs

[–] qaz 1 points 8 months ago* (last edited 8 months ago)

The mount reform has a very weak ARM CPU and 32 GB RAM at most, it's a terrible option for simulations.

[–] qaz 1 points 8 months ago

Maybe you could use a portable case (probably best to get one without glass) or carrying strap.