Assuming safe code with no COM components, P/Invoke, etc. there should be no semantic difference, but performance may be impacted. Consider: More memory under 64-bit, but references are bigger. Win some, lose some.
Anyway, here are a few useful references:
- See MSDN: Migrating 32-bit Managed Code to 64-bit. Quote:
"[...] Consider a .NET applicationthat is 100% type safe code. In thisscenario it is possible to take your.NET executable that you run on your32-bit machine and move it to the64-bit system and have it runsuccessfully. Why does this work?Since the assembly is 100% type safewe know that there are no dependencieson native code or COM objects and thatthere is no 'unsafe' code which meansthat the application runs entirelyunder the control of the CLR. The CLRguarantees that while the binary codethat is generated as the result ofJust-in-time (JIT) compilation will bedifferent between 32-bit and 64-bit,the code that executes will both besemantically the same. [...]"