Xeon E5 2686 V3 Optional Ram Configuration

neo1

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Oct 6, 2016
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I'm looking to build a Xeon workstation using a Xeon E5 2686 V3. It's to be used in a C++ environment to run real-time computations. I had previously been using an i7 4790k, but it simply wasn't cutting it.

I'm trying to understand what sort of performance impact I might get from an un-optimal ram configuration.

I currently have an Asrock X99 Extreme 3, which only has 4 DIMM slots.

I was planning to use 64gb total DDR4, so 4x 16gb modules at 2133mhz, however looking at the memory controller specs for the 2686V3 I see that that the DIMMs per channel is 3*, and I'm wondering if my planned configuration is going to cause any sort of bottleneck?

Does this mean an optional configuration would be a board with that has 12 Dimm slots, occupied by twelve modules in quad-channel configuration?

And

Would there be a performance difference between running 64gb DDR4 @ 2133mhz configured in a motherboard with 8 DDR4 DIMM slots, each occupied by 8gb modules vs a motherboard with 4 DDR4 DIMM slots, each occupied by 16gb modules ?


Thanks
 

KioskAdmin

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Jan 20, 2015
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e5-2600 chips are all quad channel memory.
e5-2400 chips are triple channel memory.

you have a quad channel CPU so run quad channel memory
 
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neo1

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e5-2600 chips are all quad channel memory.
e5-2400 chips are triple channel memory.

you have a quad channel CPU so run quad channel memory
I'm running Quad channel memory.

An 18 core processor isn't typically run on a MB with only 4 DIMM slots(Asrock X99 Extreme 3). If it was being used in a server board you would run 8- 12 DIMMs per CPU socket vs the 4 that I'll be running.

I'm basically asking if there is any performance difference between running Quad4( 4 Dimm modules) Vs Quad8 or Quad 12.
 

MiniKnight

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The only difference is that if your motherboard cannot support full speed with the RAM/ DIMM ranks you're using. If it cannot, you'll see 2400 MHz ram go to 2133. That's going to be 1-3% performance loss max so the benefit of having more RAM always outweighs a speed loss.

Need to check memory modules against manual for this.
 
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neo1

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The only difference is that if your motherboard cannot support full speed with the RAM/ DIMM ranks you're using. If it cannot, you'll see 2400 MHz ram go to 2133. That's going to be 1-3% performance loss max so the benefit of having more RAM always outweighs a speed loss.

Need to check memory modules against manual for this.
E5-2600 V3 Chips only support upto 2133.
 

wildpig1234

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i am interested in getting 2686 v3. you have any place with good price? so hard to find them in first place..