AlexKaras; described here:
the biggest advantage of having TC compiled as 64bit application is that it would have full access to all memory available on the system. They would also work "better" because they run on the same "bandwith" as the underlying architecture. The latter being just a matter of preventing possible (strange) performance issues.
Also, in more general: the wordwide standard is becoming 64bit, both in processors, as well as in Windows.
Te be modern an application which potential has heavy workload (like TC / TE) potentially have, would inho be better of as being available in 64bit as well)
Comparing TestComplete with Visual Studio is an incorrect comparison if you ask me. At least not a 100% valid one. I mean Visual Studio does not have (that much) rare performance issues (as far as I know of), and it's not working intensively with "third party" applications, as TestComplete can (since it supports all Windows based applications). In fact, now that I am thinking over it, it's actually quite logic than when you use a 64bit OS, then run a 32bit TestComplete is used tot start a 64bit application, this might just be asking for (unclear) performance / memory / processor issues: you switch from architecture 2 times (64bit -> 32bit -> 64bit)... doesn't sound very robust approach to me.