From charlesreid1

Speed Test

To speed test cowpatty, just run it with a wordfile of a short length. This will give you an estimate of how long cowpatty takes with a longer dictionary file.

For example, here is a test of cowpatty with a short wordlist:

$ wc -l short.txt 
2360 short.txt

$ cowpatty -r ./wpa.cap -f short.txt -s 64oz 
[...]
1689 passphrases tested in 6.50 seconds:  259.89 passphrases/second

250 keys per second is way slower than Aircrack's 1200 keys per second - 5 times slower.

The advantage of using cowpatty, even thought it's slower, is that you can use Rainbow Tables with cowpatty.