(I have read a great deal about 64-bit versus 32-bit OS/Applications, but this is particularly when it comes to databases.)

I am attempting to comprehend the benefits and drawbacks of 32-bit versus 64-bit databases, and namely, under what problems that it begins to create sense to make use of 64-bit installations.

The database systems that i'm thinking about are: SQL Server 2008, MySQL, and PostgreSQL 9..

I've read that pre-9. versions of PostgreSQL only is available in 32-bit for Home windows, which article about running 32-bit PostgreSQL on 64-bit Windows clears up a number of my confusion, but I am searching for more information.

When would I take advantage of using 64-bit databases (i.e. database size/disk space, available system memory, kinds of data sernarios that are recognized to take advantage of it, which database engine getting used, etc.)?

Presuming you've got a 64-bit capable OS and processor, the most crucial benefit of 64-bits is a chance to use a lot more than 4GB of memory.