[Ford Prefect]

Hi,


We are currently looking to purchase a new small cluster, to be used with CFD (OpenFOAM, COMSOL, Fluent and Star-CCM+) and also in-house thermodynamics as well as ab-initio calculations. Licenses will not be an issue.


Right now we look at a Dell R450 base node with


Processor: 2 x Xeon Silver 4314
Memory: 256 GByte
Infiniband: Mellanox ConnectX-5


Each node will be about 8 000 Euro and we will purchase 8 nodes together with an infiniband switch. One of the nodes will have a GPU with some more capability, for some codes that utilize that (so some 10 000 Euro card from Nvidia most likely).


Is this a reasonable setup or would EPYC make more sense in terms of price/performance?


EDIT:


Dell R6525 with 2 x EPYC 7313, and slightly faster memory will be about 2000 Euro more expensive per node.

[flotus1]

Is this a reasonable setup

It's pretty good, I would consider the Xeon 4314 the cheapest viable CPU for a cluster. As always, specify with your vendor how you want the memory populated. I.e. 16x16GB DDR4-2666 DIMMs.
OEMs have no problem with up-selling you faster RAM which can't be utilized by these CPUs, or just leaving memory channels unpopulated by using larger DIMMs.

That being said, it's 8000€ per node, and the CPUs are currently selling for ~700€ each.
If you really have no issues with licenses, I would try getting CPUs with slightly more cores. E.g. Xeon silver 4316. That's 25% more cores, and should not be a huge price increase relative to the 8000€ per node. They are currently selling for 1050€ each.

[wkernkamp]

DELL installs DDR4-3200 memory by default. Check if the proposed system has 16 RDIMMs installed at that frequency. Your selected CPU will only use it at 2666 speed. However, you may want to upgrade later to a Platinum cpu that will have the full memory speed potential.


Note that the chassis is limited to 24 core cpus (says DELL).

[sharonyue]

I can get the cluster with same performance at half price, lol.
The most important thing is, DO NOT go for 7313, it does not improve much.

[flotus1]

@sharonyue what was your intention when writing this post?
Sure, the second half is genuine advice. But what is OP supposed to do with the first half? Feel bad about having to buy hardware that is more expensive than what you have available?
If you wanted to make this helpful, maybe include HOW you get half the price. Do you live in a part of the world where this type of hardware is just that cheap? Or do you know a particular vendor that sells it particularly cheap, and you could recommend?

I also had to learn this the hard way, but buying computer hardware in a company setting can come with lots of strings attached. For example, you certainly want some elevated level of support and warranty, which isn't free. And although this is one of the stupidest things I ever heard in this context: some companies have exclusivity agreements with one particular vendor. Meaning no matter what they charge or offer, the company buys exclusively from them.