root@appie:/tmp/tinc-1.0.31# export OPENSSL_ia32cap="~0x200000200000000" root@appie:/tmp/tinc-1.0.31# openssl speed -elapsed -evp aes-256-cbc You have chosen to measure elapsed time instead of user CPU time. Doing aes-256-cbc for 3s on 16 size blocks: 3098099 aes-256-cbc's in 3.00s Doing aes-256-cbc for 3s on 64 size blocks: 877078 aes-256-cbc's in 3.00s Doing aes-256-cbc for 3s on 256 size blocks: 227160 aes-256-cbc's in 3.00s Doing aes-256-cbc for 3s on 1024 size blocks: 57108 aes-256-cbc's in 3.00s Doing aes-256-cbc for 3s on 8192 size blocks: 7211 aes-256-cbc's in 3.00s Doing aes-256-cbc for 3s on 16384 size blocks: 3591 aes-256-cbc's in 3.00s OpenSSL 1.1.0f 25 May 2017 built on: reproducible build, date unspecified options:bn(64,64) rc4(8x,int) des(int) aes(partial) blowfish(ptr) compiler: gcc -DDSO_DLFCN -DHAVE_DLFCN_H -DNDEBUG -DOPENSSL_THREADS -DOPENSSL_NO_STATIC_ENGINE -DOPENSSL_PIC -DOPENSSL_IA32_SSE2 -DOPENSSL_BN_ASM_MONT -DOPENSSL_BN_ASM_MONT5 -DOPENSSL_BN_ASM_GF2m -DSHA1_ASM -DSHA256_ASM -DSHA512_ASM -DRC4_ASM -DMD5_ASM -DAES_ASM -DVPAES_ASM -DBSAES_ASM -DGHASH_ASM -DECP_NISTZ256_ASM -DPADLOCK_ASM -DPOLY1305_ASM -DOPENSSLDIR="\"/usr/lib/ssl\"" -DENGINESDIR="\"/usr/lib/x86_64-linux-gnu/engines-1.1\"" The 'numbers' are in 1000s of bytes per second processed. type 16 bytes 64 bytes 256 bytes 1024 bytes 8192 bytes 16384 bytes aes-256-cbc 16523.19k 18711.00k 19384.32k 19492.86k 19690.84k 19611.65k root@appie:/tmp/tinc-1.0.31# unset OPENSSL_ia32cap root@appie:/tmp/tinc-1.0.31# openssl speed -elapsed -evp aes-256-cbc You have chosen to measure elapsed time instead of user CPU time. Doing aes-256-cbc for 3s on 16 size blocks: 12686664 aes-256-cbc's in 3.00s Doing aes-256-cbc for 3s on 64 size blocks: 5366723 aes-256-cbc's in 3.00s Doing aes-256-cbc for 3s on 256 size blocks: 1680634 aes-256-cbc's in 3.00s Doing aes-256-cbc for 3s on 1024 size blocks: 448514 aes-256-cbc's in 3.00s Doing aes-256-cbc for 3s on 8192 size blocks: 57195 aes-256-cbc's in 3.00s Doing aes-256-cbc for 3s on 16384 size blocks: 28609 aes-256-cbc's in 3.00s OpenSSL 1.1.0f 25 May 2017 built on: reproducible build, date unspecified options:bn(64,64) rc4(8x,int) des(int) aes(partial) blowfish(ptr) compiler: gcc -DDSO_DLFCN -DHAVE_DLFCN_H -DNDEBUG -DOPENSSL_THREADS -DOPENSSL_NO_STATIC_ENGINE -DOPENSSL_PIC -DOPENSSL_IA32_SSE2 -DOPENSSL_BN_ASM_MONT -DOPENSSL_BN_ASM_MONT5 -DOPENSSL_BN_ASM_GF2m -DSHA1_ASM -DSHA256_ASM -DSHA512_ASM -DRC4_ASM -DMD5_ASM -DAES_ASM -DVPAES_ASM -DBSAES_ASM -DGHASH_ASM -DECP_NISTZ256_ASM -DPADLOCK_ASM -DPOLY1305_ASM -DOPENSSLDIR="\"/usr/lib/ssl\"" -DENGINESDIR="\"/usr/lib/x86_64-linux-gnu/engines-1.1\"" The 'numbers' are in 1000s of bytes per second processed. type 16 bytes 64 bytes 256 bytes 1024 bytes 8192 bytes 16384 bytes aes-256-cbc 67662.21k 114490.09k 143414.10k 153092.78k 156180.48k 156243.29k