Keep in mind that MD5 is less secure than SHA1.
Older CPUs can calculate MD5 over twice as fast as SHA1. GPUs in parallel calculations can handle MD5 over 3 times as fast as SHA1!
Two Radeon 79xx-series GPUs can calculate a rainbow table for 6-character lowercase MD5 password in... roughly 6 seconds!
Source: http://www.codinghorror.com/blog/2012/04/speed-hashing.html