SHUTTLE 71R-J14 V10 DDR3 - REV A Schematic Circuit Diagram
IA-32e 64-Bit Extension Mode (x64, AMD64, x86-64, EM64T)
Despite the fact that 32-bit Windows may handle up to 4GB of RAM, apps can only access approximately 3.25GB of RAM. Video cards, the system ROM, integrated PCI devices, PCI and PCIe cards, and APICs use the remaining address space.
64-bit Windows can run 32-bit Windows apps without issue, but it can't run 16-bit Windows, DOS applications, or any other virtual-real-time programs. Another major issue is drivers. 64-bit dynamic link libraries (DLLs) cannot be loaded by 32-bit processes, and 32-bit DLLs cannot be loaded by 64-bit processes. This essentially means that you'll need both 32-bit and 64-bit drivers for all of the devices you've connected to your system in order for them to operate. Obtaining 64-bit drivers for older or no longer supported devices might be difficult or impossible. Check with the suppliers of your internal and add-on devices for 64-bit drivers before installing a 64-bit version of Windows.
Look for 64-bit drivers for Windows XP x64 edition if you can't locate 64-bit drivers for Windows Vista or Windows 7. These drivers frequently operate well with newer 64-bit Windows versions. Unlike a few years ago, suppliers now offer a full range of 64-bit-compatible software and drivers, allowing you to use either 32-bit or 64-bit versions of Windows with both new and older hardware. 64-bit PC processors have replaced 32-bit PC processors as the primary platform for Windows, with 32-bit versions of Windows being used largely by tablets.