Few CPU Facts

64-bit computing : In computer architecture, 64-bit computing is the use of processors that have datapath widths, integer size, and memory address widths of 64 bits (eight octets). Also, 64-bit CPU and ALU architectures are those that are based on registers, address buses, or data buses of that size. From the software perspective, 64-bit computing means the use of code with 64-bit virtual memory addresses.

Processor registers are typically divided into several groups: integer, floating-point, SIMD, control, and often special registers for address arithmetic which may have various uses and names such as address, index or base registers. However, in modern designs, these functions are often performed by more general purpose integer registers. In most processors, only integer or address-registers can be used to address data in memory; the other types of registers cannot. The size of these registers therefore normally limits the amount of directly addressable memory, even if there are registers, such as floating-point registers, that are wider.

What the difference between Intel Core i3, Core i5, Core i7:

The Core name itself is a bit misleading. All CPUs have one or more cores, with each core being a processor itself. Most commonly an Intel Core processor will have two physical cores (dual-core) and also two virtual cores (which Intel calls Hyper-Threading). Some, though, have four physical cores: quad-core. If you buy a Core i7 Extreme Edition, you will find up to 12 phyiscal cores. Physical cores are better than virtual cores in performance terms.

Model	Core i3	Core i5	Core i7
Number of cores (A core can be thought of as in individual processor)	2	4	4
Hyper-threading (Hyper-Threading is Intel's technology for creating two logical cores in each physical core)	Yes	No	Yes
Turbo boost (Turbo Boost is Intel's technology for automatically overclocking a processor, boosting its clock speed higher than the default setting)	No	Yes	Yes
K model (Any CPU that has a model ending with a K means that it the CPU is unlocked)	No	Yes	Yes

CPU Registers :
There are 16 general purpose registers in the x86-64 architecture.

ARM architecture:
ARM, originally Acorn RISC Machine, later Advanced RISC Machine, is a family of reduced instruction set computing (RISC) architectures for computer processors, configured for various environments. British company ARM Holdings develops the architecture and licenses it to other companies, who design their own products that implement one of those architectures—​​including systems-on-chips (SoC) that incorporate memory, interfaces, radios, etc. It also designs cores that implement this instruction set and licenses these designs to a number of companies that incorporate those core designs into their own products.