UPDATE: It does now (tested on AMD quad core, Windows 8.1).
Note that PHP on Windows does not support 64-bit integers at all, even if both the hardware and PHP are 64-bit. See this link for details:
On Windows x86_64, PHP_INT_MAX is 2147483647. This is because in the underlying C code, a long is 32 bit.
However, Linux on x86_64 uses a 64-bit long, so PHP_INT_MAX is going to be 9223372036854775807.