The various applications that make up 4D v11 SQL are 32-bit applications that support the 'large address space aware' flag on Windows (and equivalent on Mac OS X). What this means is 4D is able to address up to 4GiB of total memory. Applications that do not support large address spaces only use 31 of the 32 bits available for a memory address and, as such, can only address 2GiB of memory. 4D 2004 is such an application.

So in comparison 4D v11 SQL is capable of addressing twice as much memory as 4D 2004. Note however that this does not mean 4D v11 SQL can use 4GiB of memory on all systems; the amount of memory that 4D has access to is limited by the OS, not 4D, since it is the OS that handles memory management.

Nonetheless we have developed some criteria for ensuring that the maximum possible memory is available to 4D. Here are the rules to follow:

• Use 4D v11 SQL.
  
• Use a 64-bit OS.
  
• Install at least 8GB of RAM.

Assuming these conditions are met, the amount of memory available to 4D will be highest:

• 4D will be able to access 4GiB of memory on Windows.
  
• 4D will be able to access 3GiB of memory on Mac OS X.
  
• 4D will be able to allocate the largest possible database cache (usually somewhere around 1-2GiB).