LGA 3647 motherboards-6 channel?
- Thread starter LukeP
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Not too well...asymmetric hexa-channel
Assuming you populate 8 identical DIMMs per CPU, you get actual hexa-channel for the lower 3/4 of the memory. Memory allocated in the remaining 1/4 has lower bandwidth. Only do this if you know that your applications are not memory-bound and you need a total amount of memory that can not be created with 6 DIMMs
My take is that these boards were put out there simply for convenience of those used to 4 or 8 DIMM slots per CPU. From a performance standpoint, they make no sense.
Edit: judging by the suboptimal memory configurations many system vendors tried to sell when Skylake-SP was introduced, the Idea that the memory amount has to be a power of two won't go away before Intel switches to octa-channel memory.
Assuming you populate 8 identical DIMMs per CPU, you get actual hexa-channel for the lower 3/4 of the memory. Memory allocated in the remaining 1/4 has lower bandwidth. Only do this if you know that your applications are not memory-bound and you need a total amount of memory that can not be created with 6 DIMMs
My take is that these boards were put out there simply for convenience of those used to 4 or 8 DIMM slots per CPU. From a performance standpoint, they make no sense.
Edit: judging by the suboptimal memory configurations many system vendors tried to sell when Skylake-SP was introduced, the Idea that the memory amount has to be a power of two won't go away before Intel switches to octa-channel memory.
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You end up with 1 dimm per channel for some channels and 2 dimm per channel for others. Performance does not really suffer unless your really memory bound, but it’s not an ideal config for sure.
See also in the 2nd gen scalable boards the extra dimms could be dedicated to non volitile memory (Apache pass)
Some other than the Apache pass reason some vendors just wanted to have say 8 dimms to say the system has the same capacity as the e5 v4 with 2dpc / 4 channels
See also in the 2nd gen scalable boards the extra dimms could be dedicated to non volitile memory (Apache pass)
Some other than the Apache pass reason some vendors just wanted to have say 8 dimms to say the system has the same capacity as the e5 v4 with 2dpc / 4 channels
I think very few of the 8 DIMM per socket systems will be used for Apache Pass.
I expect Intel to limit SKUs that can use Optane Persistent Memory. The motherboards with 8 DIMMs per socket are popular in the lower end of the SKU stack where Apache Pass will not be applicable.
Also, Intel has been showing off Apache Pass in 6 modules per CPU configurations. If you think you want Apache Pass, you are going to get a 12 DIMM per socket motherboard.
On the 8 DIMM per socket boards, it is done for parity with Xeon E5. People are accustomed to buying servers with 8x16GB or 8x32GB per socket for generations. Vendors sought the need to achieve parity.
I expect Intel to limit SKUs that can use Optane Persistent Memory. The motherboards with 8 DIMMs per socket are popular in the lower end of the SKU stack where Apache Pass will not be applicable.
Also, Intel has been showing off Apache Pass in 6 modules per CPU configurations. If you think you want Apache Pass, you are going to get a 12 DIMM per socket motherboard.
On the 8 DIMM per socket boards, it is done for parity with Xeon E5. People are accustomed to buying servers with 8x16GB or 8x32GB per socket for generations. Vendors sought the need to achieve parity.