$ openssl speed -evp aes-256-cbc
To get the most accurate results, try to run this
program when this computer is idle.
Doing aes-256-cbc for 3s on 16 size blocks: 8913151 aes-256-cbc's in 2.95s
Doing aes-256-cbc for 3s on 64 size blocks: 2436201 aes-256-cbc's in 2.96s
Doing aes-256-cbc for 3s on 256 size blocks: 623692 aes-256-cbc's in 2.93s
Doing aes-256-cbc for 3s on 1024 size blocks: 156188 aes-256-cbc's in 2.92s
Doing aes-256-cbc for 3s on 8192 size blocks: 19405 aes-256-cbc's in 2.95s
OpenSSL 0.9.7j 04 May 2006
built on: date not available
options:bn(64,32) md2(int) rc4(idx,int) des(ptr,risc1,16,long) aes(partial) blowfish(idx) 
compiler: information not available
available timing options: USE_TOD HZ=100 [sysconf value]
timing function used: getrusage
The 'numbers' are in 1000s of bytes per second processed.
type             16 bytes     64 bytes    256 bytes   1024 bytes   8192 bytes
aes-256-cbc      48419.44k    52657.95k    54499.03k    54737.63k    53829.68k