is DES Faster Than AES on software
Yes, it is possible that AES is slower than DES. There is no limit to the slowness of un-optimized software!

Some factors that I have witnessed slowing a software AES implementation:


not using tables for computation of the S-box(es) (an extreme example is the implementation there, when compiled with BACK_TO_TABLES undefined; another possibility is using a formula intended for hardware or bitslicing, perhaps in order to remove timing variations).
using hexadecimal ASCII (or binary) strings for everything, perhaps with the excuse that there is no built-in 128-bit type;
using an interpreted language (one without built-in XOR will insure particularly poor performance)
leaving debug code that dumps every intermediary result, even if that's effectively to /dev/null or equivalent;
to a moderate degree, recomputing subkeys at each invocation when the mode of operation allows to factor that out;
to a small degree, using 256-bit keys (it is hard to lose more than a factor of two with this one).


This is also applicable to DES to a large degree.

I should have mentioned that for decently and comparably optimized implementations, AES is typically faster than TDES and often than DES, and illustrated that with throughput; but that other answer does it nicely.