The Intel Performance Acceleration Technology (PAT) is technology built on to Intel i875 Canterwood mainboards and other Pentium 4 based motherboard

Motherboard

In personal computers, a motherboard is the central printed circuit board in many modern computers and holds many of the crucial components of the system, providing connectors for other peripherals. The motherboard is sometimes alternatively known as the mainboard, system board, or, on Apple...

s that based on the Intel D875PBZ reference board. Performance Acceleration Technology delivers additional system-level performance by optimizing memory access between CPU

Central processing unit

The central processing unit is the portion of a computer system that carries out the instructions of a computer program, to perform the basic arithmetical, logical, and input/output operations of the system. The CPU plays a role somewhat analogous to the brain in the computer. The term has been in...

 and system memory, allowing increased performance to be exhibited at standard operating specification.

There are three types of Performance Mode: Disabled, Partially enabled, and fully Enabled.
There may be BIOS

BIOS

In IBM PC compatible computers, the basic input/output system , also known as the System BIOS or ROM BIOS , is a de facto standard defining a firmware interface....

 settings that affect this parameter.
The PAT status is reported by some versions of Memtest86

Memtest86

Memtest86 and Memtest86+ are open source memory test software programs designed to test and stress test an x86 architecture computer's random access memory for errors...

 and CPU-Z

CPU-Z

CPU-Z is a freeware system profiler application for Microsoft Windows that detects the central processing unit, RAM, motherboard chipset, and other hardware features of a modern personal computer, and presents the information in one window.CPU-Z is more in-depth in almost all areas than the tools...

, and at boot time by Dell motherboards.