The same motherboard slot speed will “change” PCIe channel that thing

Recently, you are considering or just saving your computer partners, when reading the manual of the motherboard did not feel something wrong. Did not notice? Then take a closer look at the motherboard slots, M.2 interface that part, you will find that obviously the same motherboard the same slot, there are actually PCIe ×16, ×8 changes, and PCIe 3.0, 4.0 different. What’s going on? Don’t worry, I’ll talk about it today.


PCIe (full name PCI Express) is a signal transmission standard for connecting various devices, similar to USB, with good versatility and can be connected to different devices; there are also different versions, the higher the version the faster the speed. The difference is that USB connects peripherals, while PCIe mainly connects various accessories on the motherboard, and can also be used in combination, PCIe ×4, ×16 is 4, 16 PCIe channels combined together.


Then the motherboard has these PCIe lanes from the processor and chipset. The number of PCIe lanes varies from processor to processor and chipset to chipset, and the versions differ. Mainstream processors generally have 10 to 20 PCIe lanes, chipsets have 12 to 16, the current common PCIe 3.0 lanes, a single transfer speed of about 1GB / s, the new PCIe 4.0 lanes have 2GB / s.


Because PCIe lane is compatible and easy to use in combination, most of the accessories on motherboards such as graphics cards and M.2 SSDs are now connected with PCIe lane, even some of the SATA interfaces, network, Wi-Fi and Bluetooth interfaces on new motherboards are actually converted to PCIe lane.


However, this makes the motherboard with PCIe place is too much, high-end processors can barely cope, low-end processors such as APU, Sprint, PCIe channel was not much, but also used eight channels even the built-in display unit, providing the motherboard with a lot less channels, only enough to give the graphics slot 8, to the M.2 interface 2, the actual speed of these interfaces has become lower.


And when installing these low-end processors, because the PCIe channel is not enough, there will be some slots, interfaces because they can not be divided into channels directly “scrapped”, or can only share the channel with other interfaces. This is the time to install a separate sound card / network card or a second M.2 SSD? The partners who have more accessories on hand must be scratching their heads.


In addition, these slots, the speed of the interface is also related to the PCIe version, the general processor can only provide PCIe 3.0 channel, and the processor directly connected to the PCIe ×16 slot has a maximum speed of 16GB / s, some new processors can provide PCIe 4.0 channel, the maximum speed of this slot is also naturally upgraded to 32GB / s. M.2 interface is also the same.


Having said that, has any partner found that I have not mentioned the chipset PCIe channel? This is because it is fixed, with the lowest-end processors, can also provide a basic enough number of interfaces and speed, so that the entry-level platform to install basic accessories no problem. Only the speed and upgrade ability, of course, is more limited Oh.


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