This would be an architecture limitation, Since (without PAE or WAE as Microsoft calls it) 32-bit integers can only address 4GB of memory for any given process. Windows Std and Enterprise will treat this the same way if they are both 32-bit. Switch to a 64-bit version of Windows if you need a single process to consume more than 4GB of RAM.
Oh. And don't use PAE or WAE. 64-bit hardware is cheap now.
*Note I am assuming that 32-bit limitations aren't hard coded into enterprise manager / ops man