[bisqik]

Hello All,

I have read a couple of dozens threads here, but I still have trouble deciding on a "perfect" workstation for my use. I hope you will be able to help me.

Currently I've got old i7-3770k, 16GB of RAM, some SSD, and it takes almost a day to finish my 700k cell simulations. It's a side project, a couple of times a month, just to get some cash. That's why I don't have the budget or need to invest in Xeon Gold server grade units. I have three choices, listed below, that I think would be best, but I need to confirm with you what is the best choice.

1)
AMD R7 2700X
ASRock X370 PRO4 or MSI, or Asus X370 with NVMe.
G.Skill Ripjaws V DDR4, 2x8GB, 3200MHz
SSD Samsung 970 EVO 250GB PCIe x4 NVMe
GPU 1050 4GB or Quadro P600
SilentiumPC Supremo L2 V2 550W

2)
Intel I5-8600k
Some Z370 motherboard
2x16GB DDR4-3200
SSD Samsung 970 EVO 250GB PCIe x4 NVMe
GPU 1050 4GB or Quadro P600
SilentiumPC Supremo L2 V2 550W

3)
Intel I7-8700k or 7700k
some compatible MOBO, priced is similar to the Z370 one
2x16GB DDR4-3200 or faster
SSD Samsung 970 EVO 250GB PCIe x4 NVMe
GPU 1050 4GB or Quadro P600
SilentiumPC Supremo L2 V2 550W

So, which would be the best for my case? And how much improvement can I expect in simulation time?

Also, do I need graphics card?
Should I get 2x8GB, or 2x16GB, or 4x4(4x8) set? Would populating 4 slots on Dual Channel processor/MOBO actually lower the performance vs 2 slots with Dual Channel?

And what type of benchmark should I look for in popular processor tests that would reflect the power for CFD simulation in the best possible way?

Thank you for your response,
Andrzej

[flotus1]

So, which would be the best for my case? And how much improvement can I expect in simulation time?

Among those three options: I5-8600k. The improvement won't be spectacular though, maybe in the order of 30%-40% shorter run times if memory runs at stock speeds on your current system.
Provided of course you are not limited by Disk-I/O in which case the new system will be much faster and investing in a larger SSD might be worth it.

Also, do I need graphics card?

Not necessarily with the Intel systems. Integrated graphics is fine for pre- and post-processing smaller models. More than a GTX 1050 2G would be wasting money for your requirements. Not sure if a Quadro GPU is worth it, that depends on the software you use aside from CFD.

Should I get 2x8GB, or 2x16GB, or 4x4(4x8) set? Would populating 4 slots on Dual Channel processor/MOBO actually lower the performance vs 2 slots with Dual Channel?

This is a more severe issue with Ryzen CPUs. Intels IMC can handle pretty much everything you throw at it. Memory overclocking for very high frequencies (in the order of DDR4-3600 and above) will work better with only 2 DIMMs populated. Populating all slots does not necessarily hurt performance provided the memory frequency stays the same.
Just look at memory usage on your current system. If you have enough memory there, 16GB will be enough on the new system.
My rule of thumb despite all of this: use as few memory modules as possible, there are no downsides as long as you populate all memory channels.
The only downside to using 2x8GB vs 2x16GB: you will most likely get single-rank DIMMs which perform a little worse for the same frequency.

And what type of benchmark should I look for in popular processor tests that would reflect the power for CFD simulation in the best possible way?

I have not come across any popular benchmark that reliably reflects CFD performance.