Lo sviluppo dei microprocessori rese col tempo sempre meno costosa l'integrazione di una unità di calcolo in virgola mobile direttamente nella [[die (elettronica)|die]] del chip per cui l'uso di coprocessori matematici esterni lentamente declinò. Uno degli ultimi coprocessori esterni è l'[[Intel 80387]] mentre una delle prime CPU che integra una [[Floating Point Unit|FPU]] è l'[[Intel 80486]]. Attualmente il loro uso nei computer desktop è ormai del tutto abbandonato mentre, invece, è sempre più vivo il bisogno di coprocessori grafici particolarmente potenti (le [[Graphics Processing Unit|GPU]]) per il sempre più elevato numero di calcoli richiesti dai [[videogioco|giochi]] in [[Computer grafica 3D|3D]].
Image:Intel 8087 arch.svg|right|thumb| i8087 and i80287 microarchitecture.]]
Image:Intel 387 arch.svg|right|thumb| i80387 microarchitecture.]]
The original [[IBM PC]] included a socket for the [[Intel 8087]] [[floating-point]] coprocessor (aka [[Floating point unit|FPU]]) which was a popular option for people using the PC for CAD or mathematics-intensive calculations. In that architecture, the coprocessor sped up floating-point arithmetic on the order of fiftyfold. Users that only used the PC for word processing, for example, saved the high cost of the coprocessor, which would not have accelerated performance of text manipulation operations.
The 8087 was tightly integrated with the 8086/8088 and responded to floating-point [[machine code]] operation codes inserted in the 8088 instruction stream. An 8088 processor without an 8087 would interpret these instructions as an internal interrupt, which could be directed to trap an error or to trigger [[emulator|emulation]] of the 8087 instructions in software. ▲
[[Image:80386with387.JPG|right|thumb|Intel 80386 CPU w/ 80387 Math Coprocessor]]
Another coprocessor for the 8086/8088 central processor was the [[Intel 8089|8089]] input/output coprocessor. It used the same programming technique as 8087 for input/output operations, such as transfer of data from memory to a peripheral device, and so reducing the load on the CPU.
But IBM didn't use it in IBM PC design and Intel stopped development of this type of coprocessor.
During the era of 8- and 16-bit desktop computers another common source of floating-point coprocessors was [[Weitek]]. The [[Intel 80386]] [[microprocessor]] used an optional "math" coprocessor (the 80387) to perform floating point operations directly in [[computer hardware|hardware]].
The Intel 80486DX processor included floating-point hardware on the chip. Intel released a cost-reduced processor, the 80486SX, that had no FP hardware, and also sold an 80487SX co-processor that essentially disabled the main processor when installed, since the 80487SX was a complete 80486DX with a different set of pin connections.
Intel processors later than the 80486 integrated floating-point hardware on the main processor chip; the advances in integration eliminated the cost advantage of selling the floating point processor as an optional element. It would be very difficult to adapt circuit-board techniques adequate at 75 MHz processor speed to meet the time-delay, power consumption, and radio-frequency interference standards required at gigahertz-range clock speeds. These on-chip floating point processors are still referred to as coprocessors because they operate in parallel with the main CPU.
The [[Motorola 68000]] family had the [[Motorola 68881|68881/68882]] coprocessors which provided similar floating-point speed acceleration as for the Intel processors. Computers using the 68000 family but not equipped with the hardware floating point processor could trap and emulate the floating-point instructions in software, which, although slower, allowed one binary version of the program to be distributed for both cases.