Is there a performance difference between 2.4 and 5GHz wireless LANs?
5GHz signals are attenuated more than 2.4GHz signals when passing through the same objects (walls, people, etc.). This can put 5GHz gear at a disadvantage for range vs. throughput performance. However, differences in receiver design can compensate for some of the difference in signal attenuation.
On the other hand, interference in the 2.4GHz band can make it impossible for wireless LANs to operate in some locations, but no problem at all for 5GHz based networks.