Beginning with the Intel®
Pentium® 4 processor, the Intel® NetBurst™
micro-architecture provides the FPU (or FOPCODE)
compatibility mode which allows for compatibility
with older floating-point instructions. The FPU
compatibility mode is a legacy switch that puts the
processor in a DOS-friendly mode for extremely old
programs. This mode is no longer needed for modern
computing environments and Intel recommends that
this compatibility mode be set to "disabled" on the
Pentium 4 processor. Intel does not expect that
disabling the FPU compatibility mode will cause
compatibility issues with applications that are
available in the market place today; in fact, the
majority of the hardware platforms shipping today
no longer support this old x87 legacy
mode.
Some motherboards
based on the Intel® 850 chipset have the FPU
compatibility mode as an option in the BIOS.
Although Intel recommends this BIOS option be
disabled as default, some motherboards may have
enabled the FPU compatibility mode. The benefit of
disabling the FOPCODE compatibility mode is better
processor performance. If your motherboard has an
FPU (or FOPCODE) compatibility mode option in BIOS,
please make sure that the default setting is
"disabled".
Additional information on the FPU compatibility
mode can be found in the IA-32 Intel Architecture
Software Developer's Manual Volume 1: Basic
Architecture, available at:
http://developer.intel.com/design/Pentium4/manuals/