in processor generations, the 80486 was the next chip to debut.
Essentially, the 486 was just a 386DX with an onboard math co-processor,
and 8k of cache. There was no new technology used, it was more
of a second generation 386. Equipped with L1 cache and burst
mode instead of the 386's prefetch unit and pipelining, the
486 performed 2-3 times the performance of the 386 at the same
came the famed Pentium. The Pentium was more or less two 486s
in parallel, so more instructions could be processed at the
same time, as long as the software could take advantage out
of it. Equipped with a 64-bit external bus, 32-bit internal
and separate 8k caches, it provided sufficient performance gains
over the 486.
Pentium Pro shortly followed the success of the original Pentium.
Being a RISC Socket 8 chip, Pentium Pro owners were forced to
buy a new motherboard to run the once top of the line processor.
On the pro, speed is achieved by dividing its processing into
more stages, allowing more work to be done with each clock cycle.
The pro had a new form of processing, which allowed instructions
to be decoupled, which means that instructions can continue
to be executed even if one pipeline is waiting for data from
memory. The Pentium would stop all processing at this point.
The Pro can execute instructions out of order allowing for smoother
processing. Three instructions could be decoded per clock compared
to the Pentiums 1-2. Like the Pentium, it is equipped with 8k
L1 cache, but to gain further speed Intel added 256k of L2 cache
as well, running at full processor speed.