25600 is the channel rate in (EDIT) MB/sec of the stick of RAM. That's 25GB/s for a 3200 MHz DDR4 stick. x8 (for 8-channels working in parallel) is 200GB/s.
As you can see, Netflix's FreeBSD optimizations have allowed EPYC to reach 194GB/s measured performance (or just under the 200GB/s theoretical). And only with VERY careful NUMA-tuning and extreme optimizations were they able to get there.
25600 is the channel rate in (EDIT) MB/sec of the stick of RAM. That's 25GB/s for a 3200 MHz DDR4 stick. x8 (for 8-channels working in parallel) is 200GB/s.
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This has been measured in practice by Netflix: https://2019.eurobsdcon.org/slides/NUMA%20Optimizations%20in...
As you can see, Netflix's FreeBSD optimizations have allowed EPYC to reach 194GB/s measured performance (or just under the 200GB/s theoretical). And only with VERY careful NUMA-tuning and extreme optimizations were they able to get there.