We are getting very slow compile times, which can take upwards of 20+ minutes on dual core 2GHz, 2G Ram machines.
A lot of this is due to the size of our solution which has grown to 70+ projects, as well as VSS which is a bottle neck in itself when you have a lot of files. (swapping out VSS is not an option unfortunately, so I don't want this to descend into a VSS bash)
We are looking at combing projects (not nice, as we like the separation of concerns, but is a good opportunity to refactor away some dead wood).
We are also looking at having multiple solutions to achieve greater separation of concerns and quicker compile times for each element of the application. This I can see will become a dll hell as we try to keep things in synch.
I am interested to know how other teams have dealt with this scaling issue, what do you do when your code base reaches a critical mass that you are wasting half the day watching the status bar deliver compile messages
UPDATE
Apologies, I neglected to mention this is a C# solution. Thanks for all the cpp suggestions, but it's been a few years since I've had to worry about headers. At a distance I say I miss C++, but I'm not sure I want to go back
EDIT:
Nice suggestions that have helped so far (not saying there aren't other nice suggestions below, just what has helped)
New 3GHz laptop - the power of lost utilization works wonders when whinging to management
Disable Anti Virus during compile
'Disconnecting' from VSS (actually the network) during compile - I may get us to remove VS-VSS integration altogether and stick to using the VSS UI
Still not rip-snorting through a compile, but every bit helps.
Orion did mention in a comment that generics may have a play also. From my tests there does appear to be a minimal performance hit, but not high enough to sure - compile times can be inconsistent due to disc activity. Due to time limitations, my tests didn't include as many Generics, or as much code, as would appear in live system, so that may accumulate. I wouldn't avoid using generics where they are supposed to be used, just for compile time performance
WORKAROUND
We are testing the practice of building new areas of the application in new solutions, importing in the latest dlls as required, them integrating them into the larger solution when we are happy with them.
We may also do them same to existing code by creating temporary solutions that just encapsulate the areas we need to work on, and throwing them away after reintegrating the code. We need to weigh up the time it will take to reintegrate this code against the time we gain by not having Rip Van Winkle like experiences with rapid recompiling during development.