Is the 2U a limitation your mandate, or literally that short on rack estate?
Given you still have to purchase the hardware, consider used EPYC components. Not much more costly then the Ryzen option but the SP3 platform has more options for 2U cooling. If you stick to (new) Ryzen, I too recommend at least 3U or taller enclosures.
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Dynatron provides really good specs on their products and has a couple of alternatives that you may want to look at. I’ll list a few that match your filter for AM4 and 2U size.
cooler type, fan size, heat diss.,noise at 20% load, at 50%, at 100% , power at 50%, at 100%
Dynatron A24: air cooled, 60mm fan, 120W, 17.0 dBA , 31.9 dBA, 51.2 dBA, 1.68 W , 9.6 W
Dynatron A47: air cooled, 60mm fan, 145W, 25.8 dBA , 44.4 dBA, 59.8 dBA, 2.76 W , 18.0 W
Dynatron A43: passive air, no fan, 120W, tbd: depends on case cooling.
Dynatron U10: air cooled, 90mm fan, 125W, 22.3 dBA , 26.1 dBA, 36.2 dBA, 0.5 W , 1.6 W
Dynatron L34: liquid, 4x 80mm fans, 250W, 24.7 dBA , 42.8 dBA, 57.1 dBA, 3.84 W , 22.8 W
Dynatron L35: liquid, 3x 80mm fans, 250W, 25.6 dBA , 47.8 dBA, 64.4 dBA, 5.52 W , 24.7 W
Dynatron L19: liquid, 2x 70mm fans, 250W, 31.7 dBA , 38.4 dBA, 46.4 dBA, 3.24 W , 7.92 W
Interesting to see the compromises in regards to performance, size, power consumption, noise. Unfortunately, we can only guess how much performance (heat dissipation) is achieved at 50% load (of fan).
IMHO a 5950X will be heat throttle with a 120W heat dissipation spec’ed cooler (A24). If you plan on overclocking I’d look at the liquid cooling options. Among those, I don’t know how they managed to achieve a 250W heat dissipation with less and smaller fans that use less power and run quieter (L19). Either there is witchcraft involved, or maybe a typo in the spec sheet somewhere 
I find retail availability not quite at the same level as other consumer brands - I was able to find most cooler models listed by reputable dealers on eBay.
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Thanks for the cooler suggestions. I’m not concerned about noise as I’m racking in my garage.
I did look at EPYC (and Threadripper) but the retail costs appear to be 10x for maybe a 2-3x performance in the benchmarks that matter to me.
What kind of deals do you see for used EPYC and where is the best place to look? Can you get to anywhere near say… 2x retail price for 5950X?
At this point I plan to design my own, but that project is paused while I wait for some fixes to WINE.
My intent is to build a motherboard module that supports Mini and Micro ATX.
Great comparison. Thank you.
Dynatron A47 looks like a good option as I don’t care about noise and covers the 5950X up to peak workload.
What might be a good 2U chassis for this? I can rack at the top and I don’t mind cutting into the case top to give some extra airflow.
The place to look for is Aliexpress. But beware of overpriced parts!
Mainboard, Supermicro H11SSL-i
https://www.aliexpress.com/item/1005005010591848.html
CPU, AMD EPYC 7551P (32c/64t)
https://www.aliexpress.com/item/1005003104642841.html
Cooler, 2U with fan:
https://www.aliexpress.com/item/1005004556694860.html
Alternative CPU, EPYC 7401P (24c/48t):
https://www.aliexpress.com/item/1005005197604081.html
Now, apart from the alternative CPU, I purchased all of the above parts from those shops earlier this year (prices then differed from current!). Also, you’ve noticed I didn’t mention RAM yet. I have this setup running on 2 sticks of 8GB RDIMMs, but as funds permit I’ll be upgrading that to 4x 32GB Samsung M393A4K40DB3-CWE sticks. Please note if you’re using different RAM sticks, they need to be RDIMM or LRDIMM, regular RAM won’t work (guess how I found out 
).
This particular mainboard comes with 2x SFF8643 connectors on the board. This is the corresponding 4xSATA breakout cable I bought for it:
https://www.aliexpress.com/item/1005004403128110.html
Lastly, I found this adapter board for 4x M.2 NVMe drive to one of the 16x slots, allowing for fast large storage access if populated with 2TB drives (which are getting cheaper by the day/week!) Requires a 4x4x4x4 bifurcation setting in BIOS for the chosen slot. I have it working with just 2 drives (both PCIe gen 3, the board doesn’t support PCIe gen 4 so paying for that is a waste of money. Until you upgrade the board that is 
).
https://www.aliexpress.com/item/1005005186941984.html
Buying used hardware has a risk, but so far all the items work. Also, buying from Aliexpress has a risk, but every time a shop did not deliver what I purchased (a few times over the past decade or so) I got my money back from Aliexpress w/o much hassle, if any at all. Worth noting that using a credit-card is actually a smart idea for Aliexpress, as it simplifies money returns.
HTH!
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hell yeah. These are great prices for EPYC.
Decided to roll the dice with Ali express. Just ordered the board + EPYC 7601 as this will comfortably outperform the 5950X and is easier to rack into 2U.
Thanks for the tips @Dutch_Master 
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Also decided to go with Rosewill RSV-Z2900U 2U Server Chassis
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I’ll be upgrading to these soon™. Do note that the manual indicates that although single and dual RAM sticks are supported, the advised minimum is 4 sticks.
Also, it’s very likely you won’t be able to log in to the BMC as the seller doesn’t provide details on the login. You can reset the BMC login/password with a Python-based CLI tool from the SuperMicro website, but be careful as it’ll reset all logins of all SM boards it’ll find on the local network! Said tool needs some digging on the SM website to find, I did post a direct link elsewhere but can’t find it ATM, sorry 
After use, the login will be ADMIN (in capitals!) and the password will be noted on the board near the CPU socket. Again, capital or lower case matters!
HTH!
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Could you please take a look and share that link?
We are using freedos with ipmicfg.exe and it takes ages…
Anyways, if someone stumbles on this thread. In the future, I want to leave a note.
Epyc is generally a good idea, it supports cheaper memory (server r dimm) , is meant for higher temperatures and 24/7 use and packs a hefty punch for its price.
However (!) it can take its toll with a steeper plunge on power, meaning your electricity bill can and will be higher.
Also certain applications generally like higher frequencies and lower core counts more, especially when talking about boost clock it can be a significant downside.
Lastly, it just my personal opinion, Epyc can be an absolute b1&€@ to install. With its massive socket, one wrong move can be very costly. Look at an Ryzen with AM4, even a toddler could look at the golden triangle and slot it correctly.
I personally are preferring epyc and its a good decision to go this route, but its important to be informed before you make a decision.
p.s. Never buy AMD PSB locked CPUs. Its not worth it, no matter how deep the discount is! This applies to Ryzen and Epyc alike.
BR!
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Had another look and remembered in which thread I posted it in. Here’s the direct link to the directory, don’t tell SuperMicro how you found it! 
https://www.supermicro.com/wdl/BMC_Unique_Password/
As for installing EPYC, I didn’t have a torque screwdriver so I couldn’t properly torque the socket installing the CPU. I did have a screwdriver with the correct Tork bit (#20, IIRC) so I carefully turned that as evenly as I could and wary not to take it too far. The cooler on top ensured proper contact pressure. I have no issues so far: temps are great, all PCIe slots work, other connections function as expected. Although this was my first EPYC build, I’ve been building PC’s for the better part of a quarter century so I entrusted myself with the task
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I was looking at 2x64GB MEM-DR464L-CL02-LR26 which newegg has for $108/stick = $216 but this isn’t as cost effective as 4x32GB M393A4K40DB3-CWE which amazon has for $145.
Going with the 64GB sticks allow for future expansion to half-TB without mixing memory models, though it seems the 4 sticks might have better performance due to parallel access.
The costs jump significantly at 128GB sticks so that is out of my budget.
BTW, Google Bard has been great for checking compatibility of components (whereas GPT has had trouble accessing up to date info). Also, I was able to list all my components and Bard looked-up the power consumption then calculated the appropriate PSU size for my needs - very cool.
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Can’t find that, link please?
You should check prices on 256GB LRDIMM-3DS. You can buy an entire server for one stick.
Those 4TB max memory figures are purely marketing stuff. 32 or 64GB are really the sweetspot for RDIMMs.
And EPYC has 8 memory channels. So each DIMM will increase bandwidth. But 8 DIMMs ain’t cheap. Be glad you didn’t buy Genoa and fill those 12 channels with DDR5.
I checked UDIMM prices for DDR4 but didn’t check RDIMMs. Seems like RDIMMs remain very stable in pricing, while the ECC UDIMMs crashed to half the price of last year.
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Ah it’s 4 x M393A4K40CB2-CTD but this is still compatible with the board:
Samsung Memory Bundle with 128GB (4 x 32GB) DDR4 PC4-21300 2666MHz RDIMM (4 x M393A4K40CB2-CTD) Registered Server Memory
The forum won’t let me post the URL but here is a broken version:
a .co/d/eADga6u
OK, found it:
That’s actually a good price. Couldn’t resist, daddy bezos got me 
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I’m tempted to start with two sticks of this 64GB ram to keep expansion options open for the future but it’s twice the price/GB…
Nemix 128GB 2x64GB DDR4-2666Mhz PC4-21300 288-Pin LRDIMM @ Amazon for $299