speed comparison of md5 and crc32 (python)

gistfile1.txt

jpepas@radium$ cat do-md5.py 
#!/usr/bin/env python
import sys
import hashlib
h = hashlib.md5()
with open(sys.argv[1], 'rb') as f:
    # thanks to https://stackoverflow.com/a/3431838/7543271
    for chunk in iter(lambda: f.read(4096 * 64), b""):
        h.update(chunk)
print h.hexdigest()

jpepas@radium$ cat do-crc.py 
#!/usr/bin/env python
import sys
import zlib
checksum = zlib.crc32(open(sys.argv[1], 'rb').read())
print "%x" % (checksum & 0xFFFFFFFF)

jpepas@radium$ cat do-crc2.py 
#!/usr/bin/env python
import sys
import zlib
with open(sys.argv[1], 'rb') as f:
    # thanks to https://stackoverflow.com/a/3431838/7543271
    # thanks to https://wiki-bsse.ethz.ch/display/DBSSEQGF/Calculating+CRC32+checksum+with+Python
    accumulator = 0
    for chunk in iter(lambda: f.read(4096 * 64), b""):
        accumulator = zlib.crc32(chunk, accumulator)
print "%x" % (accumulator & 0xFFFFFFFF)

jpepas@radium$ dd if=/dev/urandom of=random.bin bs=1m count=100
100+0 records in
100+0 records out
104857600 bytes transferred in 8.487965 secs (12353679 bytes/sec)

jpepas@radium$ export TIMEFORMAT='%3R'

jpepas@radium$ for i in 1 2 3; do time ./do-md5.py random.bin > /dev/null; done
1.159
1.169
1.170

jpepas@radium$ for i in 1 2 3; do time ./do-crc.py random.bin > /dev/null; done
0.151
0.151
0.134

jpepas@radium$ for i in 1 2 3; do time ./do-crc2.py random.bin > /dev/null; done
0.078
0.070
0.067