The third generation of microprocessors were introduced in 1978 and represented by Intel's 8086 and Zilog Z8000 processors. These were 16-bit processors that offered mini-computer like performance. All major workstation manufacturers also began developing their own RISC-based microprocessor architectures during this time. Key features of the 8086 included a 16-bit architecture, support for up to 1MB of memory, and segmented memory addressing. The 8086 established itself as the processor standard and was further developed into the 80186 and 80286 processors.

1. Third generation microprocessors
Third Generation Microprocessors
The third generation microprocessors were introduced in the year 1978, as denoted by Intel’s 8086 and the
Zilog Z8000. These were 16-bit processors with a performance like mini computers. These types of
microprocessors were different from the previous generations of microprocessors in that all main
workstation industrialists began evolving their own ISC based microprocessor architectures
Third generation
The thirdgeneration,introducedin1978, wasrepresentedbyIntel’s8086 and the ZilogZ8000, whichwere 16-bit
processors with minicomputer-like performance. The third generation came about as IC transistor counts
approached 250,000.
Motorola’sMC68020, for example,incorporatedanon-chipcache for the firsttime and the depthof the pipeline
increasedtofive or more stages.This generationof microprocessorswasdifferentfromthe previousonesinthat
all major workstation manufacturers began developing their own RISC-based microprocessor architectures
(Computer, 1996).
3rd Generation:During this period 16 bit processors werecreatedand designed using HMOS technology.
From 1979 to 1980, INTEL 8086/80186/80286 and Motorola 68000 and 68010 were developed. Speeds
of those processors were four times better than the 2nd generation processors.
Some of the “other” features in our new 3rd Generation Core vPro Processor family
The manageability and security features of the Intel Core vPro Processor platform always garner
a lot of attention, as they should. But, there’s a lot more under the covers to be aware of that helps
make the vPro platform the best one for business. I’ll be highlighting some of these features today
that are part of our third generation Core vPro Processors.
Let’s start with graphics. You will see up to a 2x increase in graphics performance compared to
our previous generation platform. The latest generation of our Intel HD Graphics also includes
DirectX 11 support. With both the cost and complexity of doing video work shrinking, and social
networking expanding, video is becoming a very common tool for businesses of all sizes. The
process of encoding video for different sources can be time consuming. Intel Quick Sync Video
helps to make this process a lot faster. This technology leverages the capabilities in Intel HD

2. Graphics to accelerate the process of converting video into different formats. Here’s a brief
overview video:
Check out the Intel Quick Sync Video website for additional details, including a list of software
products that make use of this technology.
Energy efficient performance is still one of the big cornerstones of the 3rd Generation Core vPro
processor family. You get Intel Turbo Boost Technology 2.0, which will automatically speed up
the CPU when heavy workloads are detected and there’s thermal headroom. This allows you to
get work done faster and maintain great battery life compared to previous generations that would
have to run the CPU maxed out for longer periods of time to get you the same results. In addition
to Intel Turbo Boost Technology, there’s also Intel Hyper-Threading Technology on supported
processors. This allows each processor core to run two tasks at the same time.
1978: microprocessor 8086
It belongs to the third generation of microprocessors: the size of the registers doubles
further and enters the 16-bit era. The performance gain is ten times higher than the
8080's.
Through a 20-bit data bus it is possible to direct a Mb of memory, an almost infinite
amount for those times.
The novelty of the processor was the use of memory in a segmented way. This method
defines memory in segments and the processor accesses it through the seg format:
disp, where the seg value is linked to the physical memory location where the segment
starts, while the value disp indicates the displacement of the said position memory at
the beginning of the previous segment.

3. To clarify with an example, the 4500 meters distance can be expressed in the absolute
value 4500 or with the notation 4: 500, where 4 would be the distance in kilometers,
while 500 would be meters starting from the fourth kilometer.
Likewise, a physical address can be defined by the segment's start address + its displacement.
This method allows you to support the relocation of programs, that is, the possibility that a
program can run in any segment or memory zone, without merely changing the value of the
segment log.
8086
8086 Microprocessor is an enhanced version of 8085Microprocessor that was designed by Intel
in 1976. It is a 16-bit Microprocessor having 20 address lines and16 data lines that provides up
to 1MB storage. It consists of powerful instruction set, which provides operations like
multiplication and division easily.
It supports two modes of operation, i.e. Maximum mode and Minimum mode. Maximum mode is
suitable for system having multiple processors and Minimum mode is suitable for system having
a single processor.
Features of 8086
The most prominent features of a 8086 microprocessor are as follows −
 It has an instruction queue, which is capable of storing six instruction bytes from the
memory resulting in faster processing.
 It was the first 16-bit processor having 16-bit ALU, 16-bit registers, internal data bus, and
16-bit external data bus resulting in faster processing.
 It is available in 3 versions based on the frequency of operation −
o 8086 → 5MHz
o 8086-2 → 8MHz
o (c)8086-1 → 10 MHz
 It uses two stages of pipelining, i.e. Fetch Stage and Execute Stage, which improves
performance.

4.  Fetch stage can prefetch up to 6 bytes of instructions and stores them in the queue.
 Execute stage executes these instructions.
 It has 256 vectored interrupts.
 It consists of 29,000 transistors.
Comparison of pentium processor with 80386 and 80486
1. 1. COMPARISON OFPENTIUM PROCESSORWITH80386 AND80486 PROCESSOR’S
2. 2. LIMITATIONSOF 80286 THAT LEAD TO 80386 80286 has onlya 16 bitprocessor. Maximum
segmentsize of 80286 is 64 KB. 80286 cannotbe easilyswitchedbetweenreal mode and
protectedmode because resettingwasrequired.The amountof memoryaddressablebythe
80286 is16M byte. Toincrease the overall systemperformance.
3. 3. THE 80386 MICROPROCESSOR A 32-bitmicroprocessorintroducedbyIntel in 1985. The chip
of 80386 contains132 pins. Ithas total 129 instructions. Ithas32 bitdata bus 32 bitaddress
bus. The executionof the instructionsishighlypipelinedandthe processorisdesignedto
operate ina multiuserandmultitasking. Softwarewrittenforthe 8088,8086,80186 and 80286
will alsorunon 386.
4. 4.  The addressbusiscapable of addressingover4gigabytesof physical memory.Virtual
addressingpushingthisover64terabytesof storage. 80387 coprocessorisused. The processor
can operate intwo modes: In the real mode physical addressspace is1Mbytesand maximum
size of segmentis64KB.  In the protectedmode addressspace is4G bytesand maximumsize
of segmentisuptoentire physical addressingspace.
5. 5.  80386 processorisavailable in2differentversions.  386DX  32 bitaddressbusand 32 bit
data bus.  132 pinspackage.  386SX  24 bit addressbusand 16 bitdata bus.  100 pinpackage.
 The lowercost package and ease of interfacing8bitand 16 bit memoryandperipherals.  But
the addressrange and memorytransferrate are lowerthanthat of 386DX.
6. 6. REGISTER SET-80386 Itincludedall eightgeneral purpose registersplusthe foursegment
registers. The general purpose registerswere16 bitwide inearliermachines,butin386 these
registerscanbe extendedto32 bit. Theirnew namesare EAX,EBX,ECXandso on. Two
additional 16bit segmentare includedFSandGS.
7. 7. MEMORY SYSTEM OFTHE 80386The memorybankare accessedviafourbankenable signals
BE0,BE1,BE2and BE3. Bank3 Bank2 Bank1 Bank 0 1G*8 1G*8 1G*8 1G*8 32 bitBE0,BE1,BE2 and
BE3 are active lowsignals.
8. 8. THE 80486 MICROPROCESSOR 80486 is the nextinIntel’supwardcompatible80x86
architecture. Onlyfewdifferencesbetweenthe 80486 and80386, butthese differencescreated
a significantperformance improvement. 32bit microprocessorandsame registersetas80386.
Few additional instructionswere addedtoitsinstructionset. 4gigabyte addressingspace .
9. 9. IMPROVEMENTS MADE IN 80486 OVER 80386 80486 waspoweredwitha8KB cache
memory. Thisimprovedthe speedof 80486 processorto greatextent. Some new 80486
instructionsare includedtomaintainthe cache. Itusesfourwaysetassociative cache. 80486

5. alsousesa co-processorsimilarto80387 usedwith80386. But thisco-processorisintegrated
on the chipallowsitto execute instructions3timesfasteras386/387 combination.
10. 10.  The newdesignof 80486 allowsthe instructiontoexecute withfewerclockcycles. 486 is
packedwith168 pingrid array package insteadof the 132 pinusedfor386 processor. This
additional pin’smade roomforthe additional signals. Thisnew designof 80486 allowsthe
instructiontoexecute withfewerclockcycles. These small differencesmade 80486 more
powerful processor.
11. 11. THE PENTIUMPROCESSOR
12. 12. WHY THE NAME PENTIUM ????? Intel wantedtopreventtheircompetitorsfrombranding
theirprocessorswithsimilarnames,asAMD had done withtheirAm486. The name Pentiumis
originallyderivedfrom the Greekwordpente meaningfive asthe serieswasIntels5th
generationmicroarchitecture.
13. 13. THE PENTIUMPROCESSOR Upwardcompatibilityhasbeenmaintained. Itcanrun all
programswrittenforany 80x86 line,butdoessoat a double the speedof fastest80486.
Pentiumismixture of bothCISCandRISCtechnologies. All the prior80x86 processorare
consideredasCISCprocessor. The additionof RISCaspectsleadtoadditional performance
improvement.
14. 14.  It uses64 bitdata bus to addressmemoryorganizedin8banks,eachbank contains512 MB
of data. Each bank can store a byte of data. BE7 BE6 BE5 BE4 BE3 BE2 BE1 BE0 B7 B6 B5 B4 B3
B2 B1 B0 64 bit MemorySystemof Pentium All these bankenablesignalsare active low.
15. 15. IMPROVEMENTSOF PENTIUMOVER 80X86 Separate 8KB data and instructioncache
memory. Dual Integerpipelinesare presentbutonlysingleintegerpipeline ispresentin80486.
Branch PredictionLogic.
16. 16. CACHE MEMORY The Pentiumcontainstwo8K-byte cache. An8 byte instructioncache,
whichstoresthe instruction. An8byte data cache, storesthe data usedbythe instructions. In
the 80486 withunifiedcache,aprogram that wasdata intensive quicklyfillsthe cache,allowing
lessroomfor instructions. InPentiumthiscannotoccurbecause of the separate instruction
cache.
17. 17. PIPELINING Itisa technique usedtoenable one instructiontocompletewitheachclock
cycle. InPentiumthere are twoinstructionpipelines,the Upipeline andV pipeline. These
pipelinesare responsible forexecuting80x86 instructions. DuringExecutionthe UandV
pipelines are capable of executingtwointegerinstructionsatthe same time andone floating
pointinstructions.
18. 18. PIPELININGFD E F D E F D E I1 I1 I1 I2 I2 I2 I3 I3 I3ClockCycle 1 2 3 4 5 6 7 8 9 F I1 I2 I3 I4 I5 D
I1 I2 I3 I4 I1 I2 I3 EClockCycle 1 2 3 4 5
19. 19.  On a nonpipelinedmachine 9clockcyclesare neededforthe individual fetch,decode and
execute cycle. Onapipelinedmachine fetch,decode andexecuteoperationsare performedin
parallel only5cyclesare neededtoexecutethe same three instructions. The Firstinstructions
needed3cyclesto complete. Additionalinstructionscomplete atrate of 1 percycle.
20. 20.  The Instructionpipelinesare five-stage pipelinesandcapable of independentoperations.
The Five-Stagesare,PF – PreFetchD1 – InstructionDecode D2 – AddressGenerate EX - Execute
Cache and ALU Access.WB – Write Back The U pipelinecanexecute anyprocessorinstruction
where asV pipeline onlyexecuteSimple Instruction.
21. 21. BRANCHPREDICTION LOGIC The purpose of branchpredictionlogicistoreduce the time
requiredfora branchcausedby internal delays. The microprocessorbeginspre-fetch
instructionatthe branch address. The instructions are loadedintothe instructioncache. When

6. the branch occurs, the instructionare presentandallow the branchto execute inone clock
period. If the branchpredictionlogicerrs,the branchrequiresanextrathree clockcycles.
22. 22. SPEED OF PROCESSORS The 80286 - 25 MHz The 80386 - 40MHz The 80486 - 60 MHz The
Pentium-90MHz
23. 23. THANKYOU