I am an architect purchasing a new computer for Revit 2014. Looking at Intel Xeon E5 1603 (quad core) or Intel Xeon E5 1620 v2 (quad core with hyperthreading) cpu's. Does hyperthreading have any advantages rendering in Revit?
It does if you locally rendering the file
This may help
http://betterrevit.com/tips/hyper-threading-for-revit/
Hyper-threading
Hyper-threading in Intel processors means that the OS (Windows) can schedule two data threads simultaneously. If one thread stalls, the other thread can be processed instead. It's is not quite like getting twice as many cores, but it does allow the CPU to process multiple threads more efficiently, and can be a significant boost for tasks such as rendering. Almost all i7 CPUs have Hyper-threading, which is one of the main advantages over the i5 which generally doesn't have Hyper-threading.