Technically, they produce the exact same result so they should be optimizable in pretty much the same way. However, there are more chances that the compiler will optimize the switch case with a jump table than the ifs.
I'm talking about the general case here. For 5 entries, the average number of tests performed for the ifs should be less than 2.5, assuming you order the conditions by frequency. Hardly a bottleneck to write home about unless in a very tight loop.