Architecture of x86 and x64 Processor

 x86 Architecture processor:

x86 belongs to the family of backwards compatible instruction set architecture. 32-bit processors were introduced in 1978. First their processor were 16-bit but later in 1985 32-bit versions were introduced. x86 emerged from the famous Intel 8086 processor. The architecture of x86 consists of 32-bit registers, 32-bit memory address and 32-bit data bus. A 32-bit processor can access a maximum of 4 GB of memory. It's a Register-Memory type of a processor. It supports a 32-bit operating system. The architecture is called x86 because the earliest processors in this family were identified by model numbers ending in the sequence "86": the 8086, the 80186, the 80286, the 386, and the 486. 

 x64 Architecture processor:

 It is the improved version of x86 instruction set architecture. It is a 64-bit processor. 64-bit processors were introduced in 2000. The architecture of x64 consists of 64-bit registers, 64-bit memory address and 64-bit data bus. It supports large amount of virtual memory and physical memory. These processors can access memory up to 8 TB. Both 32-bit and 64-bit operating systems are compatible with this type of processor.

Difference between x64 Architecture processor: 
• x86 was introduced in around year 1978 while x64 came up more recently in year 2000.

• x86 emerged from the famous Intel 8086 processor and, therefore, x86 was introduced by Intel. But x64, which came as an extension to x86, was introduced by AMD.

• x86 architecture is 32bit. (First x86 processors were 16 bit but, in later processors, an extension to 32bit was done). x64 architecture is 64 bit.

• Processors with x86 instruction set architecture, therefore, has 32 bit registers, 32 bit memory bus, and 32 bit data bus. But x64 has 64 bit registers, 64 bit memory bus, and 64 bit data bus.

• x86 has a limitation on maximum addressable memory that is an upper limit of 4 GB ( 232 bytes). But, on x64 systems, this limit is huge, which is 264 bytes.

• x64 is an expansion of x86; therefore, it is much improved and powerful than the old x86.

• Values that can be stored in a register, in a x64 system, is larger than a values that can be stored in a x86 based register. Therefore, x64 can handle computation of larger integers much faster, as there is no necessity to use several registers in such case to split the value and store as in x86.

• x64 can parallel transmit larger size data along the data bus. That is, a data bus of 64 bit can parallel transmit 64 bits while the x86 architecture that has a 32 bit bus can only parallel transmit 32 bits.

Why prefer a x64 Architecture processor:

As mentioned earlier x64 is an extension for the x86 processor. A number of things are improved and some special features are introduced in x64 architecture. Memory processing of x64 is far better and quicker than x86. x64 supports 32-bit programs as they are backwards compatible. It is faster and more reliable. 


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