@olivierlambert thank you for the quick answers, just to put it into context the plan was to use accelerated Wireguard VPN in pfSense+ which comes with own FreeBSD optimized kernel modules:
Some more info on CPU extensions / QAT / IPSsec-MB / AES-NI related to that:
https://github.com/intel/intel-ipsec-mb
https://docs.netgate.com/pfsense/en/latest/hardware/cryptographic-accelerators.html
https://networkbuilders.intel.com/docs/networkbuilders/intel-avx-512-and-intel-qat-accelerate-wireguard-processing-with-intel-xeon-d-2700-processor-technology-guide-1647024663.pdf
https://2023.asiabsdcon.org/program/_p05b/paper.pdf
https://forum.opnsense.org/index.php?topic=37808.0
https://forum.netgate.com/topic/173606/solved-intel-qat-driver-with-wireguard-support/9
https://github.com/pfsense/FreeBSD-src/blob/devel-main/sys/dev/qat/include/common/adf_accel_devices.h#L38
Example CPU's having the relevant features incl. AVX-512:
https://ark.intel.com/content/www/de/de/ark/products/226102/intel-xeon-d-1713nt-processor-10m-cache-up-to-3-50-ghz.html
https://ark.intel.com/content/www/de/de/ark/products/226113/intel-xeon-d-1722ne-processor-10m-cache-up-to-2-70-ghz.html
Some older Atoms have Intel SSE4.2 but miss the AVX-512 which i think bring the most performance:
https://ark.intel.com/content/www/de/de/ark/products/97937/intel-atom-processor-c3558-8m-cache-up-to-2-20-ghz.html
https://ark.intel.com/content/www/de/de/ark/products/134803/intel-atom-processor-c5115-9m-cache-2-8ghz.html
Best regards