So I have been testing, again.
My hapless test subject this time is a Dell Box, an R630.
It has a comfortable 384GB of memory, one of two 25 GBit/s ports active, and it comes with two E5-2690v4 CPUs. That gives it 14 cores per die, 28 cores in total, or with hyperthreading, 56 threads.
$ cat /proc/cpuinfo | grep 'model name' | uniq -c 56 model name : Intel(R) Xeon(R) CPU E5-2690 v4 @ 2.60GHz $ ./mprime -v Mersenne Prime Test Program: Linux64,Prime95,v28.10,build 1