I\'m getting the error when I run my PHP script....
Fatal error: Out of memory (allocated 1827405824) (tried to allocate 88800 bytes)
I\'ve
You're running on a 64-bit operating system, but Apache and PHP are likely still 32-bit. If you're using mod_php, apache would be the limiting factor here.
32-bit processes are limited about 2GiB of RAM unless you used the /3GB switch and the software is aware of 3GB support.
That still leaves up about 200 MiB that seems unused, but its small enough that it can be used by various libraries that all have to be loaded in memory
As far as I know, the library usage won't show up in the committed memory, but still counts towards the 2GiB limit (much like device memory counts towards the 4GiB limit on 32-bit windows. Where installing 2 GiB graphics card brings you down to under 2GiB of usable RAM).
Most likely solution? Install a 64-bit PHP, and then dispatch it to that (using a system() call, perhaps)