Max amount of RAM Win7 will reconize

The limits in Windows are a reflection of limitations in the CPU chips themselves. Even if you use a 64-bit CPU chip, the page tables and address lines on the FSB limit the amount of memory that can be connected to around 40 bits or so of memory addressing, depending on the CPU.

For example, Core 2 processors are limited to 8GB of physical memory, Core i7 9xx / Xeon W35xx CPUs are limited to 64GB, and Xeon W55xx CPUs are limited to 192GB.

See: http://www.intel.com/Assets/en_US/PDF/prodbrief/workstation-brief.pdf