Supermicro X11DPI-N Part Selection

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rrubberr

Light Transport Enthusiast
Good evening all.

Recently I purchased an X11DPI-N (revision 1.21) motherboard with the intention of installing it into a Supermicro 745TQ-r1200b chassis that has been sitting around for about two years without a system in it. However, with my current system being Xeon E5 V2 vintage, I’m a bit out of my depth with modern hardware.

That being said, help with part choice would be greatly appreciated. I have some questions which outline my situation and which will hopefully help guide the conversation.

Question 1: The top-SKU processors (28 core first generation Xeon Platinums) operate with six memory channels. This motherboard has eight DIMM slots per CPU. Is there a reason to populate more than six slots per socket when using a 6 channel processor, and would having 8 DIMMS connected to a 6 channel processor be detrimental to performance? My current machine has 192GB of memory, and optimally I would be increasing that to at least 256GB on this system, however if populating 6 slots per CPU is the better choice, I will need to purchase 32GB modules rather than 16GB.

Question 2: I assume, based on what I’ve heard about AMD Epyc processors, that these processors will be memory-speed sensitive. Typically you can save some money by going with slower memory, for instance DDR4 2133 instead of 2666. The main application of this system will be large scale ray-tracing of complex scenes and animations, often with multiple users. On GPUs this application is extremely memory-bandwidth and latency sensitive. Is DDR4 2666 a must with these processors?

Question 3: For corporate users the pricing of Xeon Scalable processors makes more sense than it does for small-scale users. I am aware of Engineering Sample (ES) CPUs and the pros and cons of using this pre-production hardware. However, at a cost reduction of 60-80% over production parts, these make sense from a budget standpoint. Could someone point me in the direction of information or experiences with Skylake ES hardware? Do you have any experience with it? Do ES processors tend to croak out of the box like bad hard drives, or is it a perpetual Russian Roulette of CPU failure? Stability is critical, and the system will be expected to run for multiple days with 100% CPU load.

Question 4: The sweet spot for 81XX processors for non-AVX heavy workloads seems to be the 8176, due to the reduced power consumption and heat with a more reasonable 165 watt TDP. Is there a lower core count, higher clocked Xeon Scalable processor which performs similarly in true many-threaded use cases?

In any case, hopefully I have posted this in the correct place. Thanks in advance for the advice, I am sure I will come up with more questions.