Requirements for a top-level computer for OpenMC

User Support
1

Dear All,

I need a new workstation for OpenMC simulations, and I would like to buy the best possible one, given the available funds.

Regarding the processor, I started considering the AMD Ryzen Threadripper PRO series 7000/9000. In particular, the models 9995WX and 7995WX. Both have 96/192 CPU/Threads with a clock frequency of 2.5 GHz.

A vendor is proposing a Lenovo ThinkStation P8 based on these processors, equipped with 128 GB of RAM, DDR5 6400, and an NVIDIA GeForce RTX 5090 32GB GDDR7. The quote is 16700 and 16000 EUR (VAT excl.) for the 9995WX and 7995WX, respectively.

However, a second vendor is proposing a machine based on the processor Epyc 9755 (128/256 CPU/Threads, 2.7 GHz) and equipped with 512 GB of RAM, DDR5 5600, and an NVIDIA GeForce RTX 5070 12GB for 17600 EUR (VAT excl.).

This second offer was a surprise for me as I had not considered that kind of processor.

According to an old post ( Speeds and other specs for an OpenMC desktop - #2 by paulromano ), among the most important requirements we can list the number of processors and the amount of L3 cache. On both these aspects, the Epyc 9755 is winning, as, other than having more processors, the L3 cache is doubling that of both 9995WX and 7995WX (512 MB against 256 MB). Moreover, Epyc has 12 memory channels while the Threadripper PRO has 8, and the 512 GB of RAM would imply almost 4 GB per CPU.

For a very similar price (but I do not have the exact quotation yet), I could get a dual Epyc 9654 (96/192 CPU/Threads each, 2.4 GHz, 384 MB L3 cache), thus increasing the number of CPUs by 50% at the cost of a 25% reduction of the L3 cache.

Do any of you have experience with these processors (Threadripper PRO and Epyc)?

Do you have any advice?

Finally, I recently saw a GitHub project for porting OpenMC from CPU to GPU. I attempted to compile the current version for my workstation, which has an NVIDIA Quadro RTX 4000, but unfortunately, I got some errors that I was not able to solve. How worthwhile is it to equip the new machine with a good GPU for a possible future use with OpenMC? Can the GeForce 5070 or 5080 be considered a good starting point?

Any comment or suggestion is more than welcome.

2

I am also intending to do such machine, and I read a lot of it, I would go with the Ebyc solution, since it is heavy duty work server process

3

Thank you @salemphi. I am currently in favour of that solution too.

In the meantime, I also received the quotation for the dual Epyc 9654: 17140 EUR (VAT excl.). To note that this configuration is equipped with two NVIDIA GeForce RTX 5070 TI 16GB.

4

I would forgo the RTXs for now.

The OpenMC GPU solver is still aways off from production use.
Many of the normal, major features of the CPU release are not implemented in the GPU version.

The Epyc is probably best for your needs.

5

@yrrepy Thanks for your comment.