[Khaza]

Hi

I have a doubt. I was hoping you could help me in clarification. I bought DELL Precision 7710 Mobile Workstation . I want to Perform 2 -way Fluid Structure Interaction and transient analysis using ANSYS Fluent.

I have single processor and 64 GB (4*16) Ram . The number of cores in Xeon E3 - 1535 V5 is 4.
http://ark.intel.com/products/89610/...Cache-2_90-GHz .

But in above link it says the maximum memory channels in 2. But my laptop is configured with (4*16, is this means I have 4 channels? )?

are these 4 channels distributed for 4 cores evenly to get optimum performance ? ( I am skeptical).

Do you think I can get optimum performance with this configuration? If not please help me with configuration so that I can change to get the maximum, performance.

Thank a lot in advance

[wyldckat]

Quick answer:

• Your laptop has 4 memory slots and they are all occupied with RAM modules, therefore it has 4 RAM modules installed.
• The CPU has 2 memory channels, which means that it's only able to access 2 memory slots at the same time. This means that it can only access one pair at a time.
• The CPU has 4 cores, in which all share the same memory channels.
• In essence, all 4 cores will schedule memory accesses and those accesses are done using 2 memory channels, making it 2x times faster than using just one memory channel.
• The idea that 2 cores are sharing 1 memory channel should not happen in this CPU in particular.

Improving performance:

• Do not use more than 4 cores to run your simulations.
• Letting HyperThreading (HT) turned on in the BIOS can help if you're using the machine as a workstation as well, i.e. if you need use the computer while a simulation is running.
  • If you're using the machine for pure computational power, then turn off HT.

[Khaza]

Originally Posted by wyldckat

Quick answer:

• Your laptop has 4 memory slots and they are all occupied with RAM modules, therefore it has 4 RAM modules installed.
• The CPU has 2 memory channels, which means that it's only able to access 2 memory slots at the same time. This means that it can only access one pair at a time.
• The CPU has 4 cores, in which all share the same memory channels.
• In essence, all 4 cores will schedule memory accesses and those accesses are done using 2 memory channels, making it 2x times faster than using just one memory channel.
• The idea that 2 cores are sharing 1 memory channel should not happen in this CPU in particular.

Improving performance:

• Do not use more than 4 cores to run your simulations.
• Letting HyperThreading (HT) turned on in the BIOS can help if you're using the machine as a workstation as well, i.e. if you need use the computer while a simulation is running.
  • If you're using the machine for pure computational power, then turn off HT.

Thank you very much the information. I need one more help.

1. Do u suggest me to change memory (4*16 ) to (2*32) so that 2 memory channel can access 2 slots of 32 GB each ?
2. If I change this , is the performance is much faster than previous setting?

Thank you very much in advance

[wyldckat]

Originally Posted by Khaza

1. Do u suggest me to change memory (4*16 ) to (2*32) so that 2 memory channel can access 2 slots of 32 GB each ?
2. If I change this , is the performance is much faster than previous setting?

I doubt you will see much of an improvement. Possibly it will be 2 to 60 seconds faster for a 24h run, when using only 2 memory slots/modules!?

[Khaza]

Originally Posted by wyldckat

I doubt you will see much of an improvement. Possibly it will be 2 to 60 seconds faster for a 24h run, when using only 2 memory slots/modules!?

So do u suggest me to keep the same setting (4*16) since you are saying there is not much difference? because I haven't asked Dell support to change to (2*32) setting.

Please give me a final call on this. I am very grateful to you.

Thanks so much for taking time to answer my doubts.

[flotus1]

There are no 32GB SODIMM-DDR4 modules and I dont know if the CPU supports DIMMs with more than 16GB.
If the memory configuration has any significant impact on performace at all, it will be the other way round: 4 DIMMs might be slightly faster than 2 DIMMs. But we are talking about differences in the order of a few percent.

[Khaza]

Originally Posted by flotus1

There are no 32GB SODIMM-DDR4 modules and I dont know if the CPU supports DIMMs with more than 16GB at all.
If the memory configuration has any impact on performace at all, it will be the other way round: 4 DIMMs might be slightly faster than 2 DIMMs.

Thanks so much for reply. So do u suggest me to keep this configuration (4*16 GB RAM ) ?

I would appreciate if u can give me some tips to use my prosessor (Xeon E3 1535V5 ) and memory (4*16 Gb) efficiently to get optimum performance.

Thanks so much for your time.

[flotus1]

There is not much you can do to improve the performance of a laptop.
Just make sure that the power saving features in the bios and operating system do not prevent the CPU from running with its maximum frequency when required. And use the laptop with battery AND power cord plugged in at the same time. Some laptops throttle the CPU when one of the two are missing.

[Khaza]

Originally Posted by flotus1

There is not much you can do to improve the performance of a laptop.
Just make sure that the power saving features in the bios and operating system do not prevent the CPU from running with its maximum frequency when required. And use the laptop with battery AND power cord plugged in at the same time. Some laptops throttle the CPU when one of the two are missing.

Thanks for the tips. Will keep them in mind.

[evcelica]

Originally Posted by flotus1

If the memory configuration has any significant impact on performace at all, it will be the other way round: 4 DIMMs might be slightly faster than 2 DIMMs. But we are talking about differences in the order of a few percent.

This is what I read in the past as well, 2 DIMMs per channel gives slightly better performance than only one. But the difference is pretty indistinguishable, and other factors should drive the memory choice more than this.