Dual E5-2630 vs dual E5-2650
 

Good morning all!
I'm planning to build my personal workstation; I read some posts in this forum and I'd want to have your suggestions about my choices.
I have 2 options:

First one:
- Mainboard: Asus Z9PE-D8 WS
- Processors: 2x Intel Xeon E5-2650 (8 cores + hyper threading)
- RAM Memory: 64 gb (8x8), DDR 3, 1600 MHz (maximum supported by these processors), non ECC
- Graphic card: Nvidia Quadro 600

Second one:
- Mainboard: Asus Z9PE-D8 WS
- Processors: 2x Intel Xeon E5-2630 (6 cores + hyper threading)
- RAM Memory: 64 gb (8x8), DDR 3, 1333 MHz (maximum supported by these processors), non ECC
- Graphic card: Nvidia Quadro 600

Advantages of first solution:
- Faster memory frequency
- 2 more cores (total of +4 cores)

Advantages of second solution:
- Better Ratio RAM/core (64 gb/12 core) = 5,3 gb per core
- Lower cost

Question is: does it worth to opt for the second solution?
Problems to be solved with fluent: 10 million cells and more

PS: workstation will be connected at university, "no limit" for parallel cores license.

Thank you!

"RAM/core" is a pretty irrelevant metric, so the more expensive one is better in every way. It's really up to you. Is a few hundred dollars worth 10%-25% faster solutions times?

Thank you very much for your comment; Difference in price is 1100 euros, so not a few bucks..I think I will go for the 2x e5-2630 for a total of 3450 euros.

About 10%-25% faster solutions times, joking:
La pazienza è la virtù dei forti
Patience is a virtue

:D

Daniele

Do you need so much memory per core? I read somewhere that people suggest 8 to 32 cores per million grids for Fluent. And usually it cost less than 4GB per million grids. That means reasonable memory core ratio shall be less than 1 GB/2.

For the fluent calculation you don't need so much ram (but it depends on the number of cells and type of case..you know, for about 3-4 million cells with k-epsilon model only, I think you need about 10-15gb); but my 64 gb are very usefull for post-processing in third party softwares (expecially transient cases and dynamic meshes); Also, sometimes a friend of mine uses my workstation with comsol and he runs cases which require 64gb+ ram.
In fluent I never run cases which required more than 40gb of ram.

PS: now I'm with 2x xeon e5-2687w and 64gb ram ecc overclocked at 1600 Mhz

If the cost for the licenses is not relevant but the price for the hardware is, you might aswell use AMD CPUs.

They will have a lower performance per core, but you can easily put together a system with 4 CPUs at the same price of the more expensive intel system.
The effective memory bandwith will be doubled, and as benchmarks have shown, this will double the performance of CFD calculations.

Edit: Now when the alternative is a quite expensive Intel CPU like the e5-2687 you can definitely buld a faster 4-CPU AMD system at a lower cost.
Edit2: Why overclocked Ram? 1600Mhz is available off the shelf, there are even some 1866Mhz modules available.

Thanks for your helpful answer. I never considered AMD CPUs before. This is a good hint. Fluent support suggests Intel Xeon to me because of the turbo boost technology. I read on this forum that, if the license cost is ignored, the memory bandwidth (GB/s) per dollar drive choice of the hardware. Even though there are also factors, this is the most important one as you said.

But there are also posts telling that AMD CPUs are too bad when they are compared with Intel Xeon so that this factor even overcomes the factor of the bandwidth. I’m really wondering how much worse are AMD CPUs than Intel Xeon (for Fluent) for the same price? How to compare them?

We don't have a problem of the fluent license number. We can easily rent or borrow licenses from our supplier company at the neighbor.

Btw, you said 'The effective memory bandwith will be doubled, and as benchmarks have shown, this will double the performance of CFD calculations.' What do you mean by 'benchmarks' here?

It is correct that the Opteron Cpus dont stand a chance against Xeons in many benchmarks.
But not in CFD-related benchmarks.
http://www.cfd-online.com/Forums/har...n-vs-xeon.html

I had no good experience with amd cpu, so no more amd in my life...
I had that ram at 1333 Mhz so instead of buying new sticks I simply overclocked them.
If cpu doesn't support 1866 Mhz (e5-2687w support max 1600 Mhz) having the ram at that frequence will be of no use.