Lis chaque section en anglais. Le resume en francais ("En bref") est juste un filet de securite : essaie de comprendre en anglais d'abord.
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The motherboard is a crucial component found in most electronic devices, including computers. Key motherboard parts include the CPU socket, RAM slots, and expansion slots.
At the heart of every computer is the processor, also called the central processing unit (CPU) or microprocessor. It executes instructions, performs calculations, and coordinates input/output operations. The major processor manufacturers today are Intel, VIA, Samsung, NVIDIA, Apple Inc., Qualcomm, and AMD (Advanced Micro Devices, Inc.) - Intel and AMD are the predominant manufacturers of desktop and laptop processors.
A term related to Intel and AMD CPUs is x86-64. "x86" refers back to the Intel 8086 processor, and "64" (or x64) is an updated 64-bit version. Intel and AMD each have their own patented CPU architecture, called Intel 64 and AMD64.
ARM processors are used on mobile devices like smartphones, tablets, and laptops (but can also be used for desktops and servers). ARM used to be an acronym for Acorn RISC (reduced instruction set computing) Machine, and later Advanced RISC Machines, but today it is just an architecture name. ARM processors can be 32- or 64-bit and take less power, produce less heat, and cost less than AMD or Intel processors.
A system on a chip (SoC) has everything needed to run the computer on a single chip: CPU, RAM, graphics processor, ports, etc. SoCs are used in desktops and mobile devices like tablets, smartphones, and laptops.
A motherboard only accepts processors from one or more specific manufacturers - for example, a motherboard built for an Intel processor will not support an AMD processor.
Central processing unit (CPU) or microprocessor.
Any of: takes less power, produces less heat, costs less.
The CPU, RAM, graphics processor, ports, etc.
No - a motherboard only accepts processors from the manufacturer(s) it was designed for.
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Processors come in a variety of speeds, measured in gigahertz (GHz). Hertz is cycles per second: 1 Hz = 1 cycle per second, and 1 GHz = 1 billion cycles per second. Today's processors can run at speeds near 6 GHz.
Processors operate on 1s and 0s, which must travel from place to place inside the processor and out to other chips. The electronic lines that move this data are called a bus. The lines inside the CPU are the internal data bus. For the CPU to communicate with the outside world (such as a printer), the 1s and 0s travel on the external data bus, also called the external data path - visible as lines on the motherboard between the expansion slots. Today's processors have 64- and 128-bit external data paths.
The larger the bus (more "lanes"), the better the performance - similar to how more highway lanes reduce traffic congestion. Each letter of the alphabet is a combination of eight 1s and 0s to the computer (for example, the letter D is 01000100).
Near 6 GHz.
The internal data bus moves data inside the CPU; the external data bus lets the CPU communicate with outside devices/components.
64- and 128-bit.
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A processor usually operates below its maximum speed to save power or prevent overheating. A processor also does not always run at its maximum potential for many reasons: coding used within an application, the user switching between applications, inadequate bus width, or the amount of RAM installed. A processor can also operate beyond its rated specifications to handle periods of increased workload.
An easy way to check processor speed in Windows is File Explorer > right-click This PC > Properties. On a Mac, use the Activity Monitor tool.
An important concept related to processor speed is keeping data flowing into the processor. The data or instruction the CPU needs is usually found in one of four places: cache memory, motherboard memory (main memory/RAM), a solid-state drive (SSD), or the hard drive. Cache memory is a very fast type of memory designed to increase the speed and efficiency of processor operations, and it provides the fastest access. If the data is not in cache, the processor looks in motherboard RAM; if it's not there either, it is retrieved from the hard drive and placed into motherboard memory or cache. Hard drive access is the slowest of the three.
| Term | Explanation |
|---|---|
| Clock or clock speed | The speed of the processor's internal clock, measured in gigahertz. |
| Front side bus (FSB) | The speed (commonly called motherboard speed) between the CPU and some motherboard components, sometimes listed in megatransfers per second (MT/s). MT/s considers both the FSB speed and the number of processor transfers per clock cycle - for example, a 266 MHz FSB doing four transfers per second could be listed as 1,064 MT/s. |
| Back side bus | The speed between the CPU and the L2 cache, which is located outside the main CPU but on the same chip. |
| PCI bus speed | The speed used to deliver data on the PCI bus. Common speeds are 33 and 66 MHz, allowing bandwidths up to 533 MB/s. |
| PCIe bus speed | The speed used to deliver data on the PCIe bus: PCIe 3.x = 8 GT/s, PCIe 4.x = 16 GT/s, PCIe 5.x = 32 GT/s, PCIe 6.x = 64 GT/s, PCIe 7.x = 128 GT/s. Total throughput = transfer rate x number of lanes. Example: PCIe 5.x at 32.0 GT/s gives 3.2 GB/s throughput on a 1x card and 512 GB/s on a 16x card. |
| CPU speed | The speed at which the CPU operates; it can be changed on some motherboards. |
| CPU throttling | Reducing the clock frequency to slow the CPU, in order to reduce power consumption and heat. Especially useful in laptops and mobile devices. |
| Type | Explanation |
|---|---|
| L1 cache | Cache memory integrated into the processor - the fastest type. |
| L2 cache | Cache in the processor packaging but not part of the CPU itself; also called on-die cache. |
| L3 cache | Usually found in more powerful processors; can be located in the CPU housing (on-die) or on the motherboard. |
Cache memory first (fastest), then RAM, then the hard drive (slowest).
L1 cache.
It reduces the clock frequency to lower power use and heat - useful in laptops to save battery and manage heat in a small case.
File Explorer > right-click This PC > Properties.
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In older computers, a performance bottleneck occurred because the CPU used a single shared bus for accessing L2 cache, RAM, and other motherboard components, limiting transfer speed. The solution was to use two buses: a back side bus (connects the CPU to the L2 cache) and a front side bus (connects the CPU to the motherboard components). The front side bus is considered the speed of the motherboard.
Many people think a higher CPU speed always means a faster computer - this is seldom true. Several factors contribute to overall speed: bus speed (how fast the CPU communicates with motherboard components like memory, the chipset, or the PCI/PCIe bus) and the chipset (which determines the maximum amount of memory, the type of memory chips, the number and type of USB ports, etc.). The chipset motherboard component looks like a processor and may have a heat sink on top.
Intel and AMD have technologies to replace the front side bus in some parts. AMD's solution connects processor cores directly to memory, other motherboard components (like expansion slots), and other cores, using a high-speed bus called HyperTransport (being upgraded to Infinity Fabric). Intel has Quick Path Interconnect (QPI), Ultra Path Interconnect (UPI), Serial Peripheral Interface (SPI), and Direct Media Interface (DMI) - point-to-point connections between the processor and one or more motherboard components.
The bus that connects the CPU to the motherboard components; it is considered the speed of the motherboard.