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Expansion slots on the motherboard used to be varied, for example, once very popular combination is the PCI slot with AGP slot, which is mainly used in the AGP slot graphics card, and use the PCI slot is broader, not only Useful in the card, but also other equipment used to expand, such as network cards, sound cards, modems and the like. Both slots have been together for many years served the majority of DIY players, but after a higher rate, more scalable slot appeared, they quickly leave the stage, it was completely replaced by the latter. And this can be eliminated in a short time the new slot predecessors, is the protagonist of our story today, is now mainstream graphics card slot as well as a variety of expansion cards used, namely PCI-E slot.
Currently PCI-E slot has become the main expansion slots on the motherboard, video card will be used in addition to the external PCI-E slot, such as a separate sound card, network card independent, USB 3.0 / 3.1 interface expansion card and other hardware can be used SSD PCI-E slot, so now the board unless the board is limited by type or platform chip, otherwise manufacturers will give them fitted with a sufficient number of PCI-E slots to ensure scalability of its products to meet the needs of players . Just PCI-E slot on the motherboard which have long or short, then what is the difference between them?
PCI-E slot relevant norms
Before we understand the PCI-E slot, first take a brief look at PCI-E of the relevant norms. PCI-E specification, also known as the PCI Express specification, which was developed by the PCI-SIG organization, which was established in 1992, members include Intel, AMD, NVIDIA, HP, Dell, Qualcomm, Lenovo, IBM and other industry leader in more than 900 elite enterprises, in addition to the existing PCI-E specification, the early years of the PCI specification and PCI-X specification is developed by the organization.
Based on half-duplex shared with parallel architectures and the development of PCI and AGP different specification, PCI-E specification is based on full-duplex point to point serial architecture developed, but also supports hot-swappable, each of which represents the full-duplex PCI-E channel in the same period may be bidirectional data transmission; means that each point is independent PCI-E connector device, it does not need to request the entire bus bandwidth; signal serial transmission rate can be allowed to easily reach GT / s (considerable in GHz) level.
Currently PCI-E specification has developed five major versions, every major version of evolution, compared to the previous version can bring the near-doubling of bandwidth. The first formal specification of the PCI-E PCI-E 1.0 is born in 2002, which is a signal rate 2.5GT / s, using 8b / 10b encoding, unidirectional single-channel bandwidth of 250MB / s, 16-channel bidirectional bandwidth, of 8GB / s. The specification also subsequently developed a PCI-E 1.0a and PCI-E 1.1 version, although there are a lot of improvements on details but the bandwidth has not changed.
PCI-E 2.0 specification is officially released in 2007, the biggest change compared to PCI-E 1.x specification signal rate is doubled to 5GT / s, so the bandwidth is doubled with follow, single-channel unidirectional bandwidth is 500MB / s, 16-channel bidirectional bandwidth of 16GB / s. Further PCI-E 2.0 specification corresponding to the power supply capacity will be doubled to slot the highest level of 150W, but for many considerations of compatibility and pressure board power supply, wherever the motherboard manufacturers, or other graphics card manufacturers and PCI- E equipment manufacturers in product development are in accordance with the power requirements of PCI-E 1.0 specification is the implementation of 75W, 75W power supply is higher than demand by all configured external power supply, the industry rule still in use.
PCI-E 3.0 specification is currently the mainstream, its official release in 2010, up to 8GT / s compared to PCI-E 2.x specification not only signal rate, and encoding turned into a more efficient 128b / 130b mode therefore still achieved single-channel unidirectional bandwidth upgrade nearly doubled, reaching the level of 985MB / s, 16-channel two-way bandwidth of up to 31.5GB / s.
PCI-E 5.0 specification to 2019 to complete the development of the official version
PCI-E 4.0 and PCI-E 5.0 specification is part of the future of the former was launched at the end of October this year, the official version, which once again achieved double the rate signal, 16 channel bi-level bandwidth of 63GB / s of; then who plans to 2019 before being released official version of the specification, can still bring the signal rate doubled and doubled bandwidth, 16-channel two-way bandwidth of 126GB / s. However, based on the promotion of devices PCI-E 4.0 specification is currently still in development and testing phase, is expected to be by the end of 2018 in order to enter the consumer market, PCI-E 5.0 specification is probably the earliest until 2020 to begin.
PCI-E slot in the end look like?
And often for different CPU socket, PCI-E specification has been developed, although five versions, but the basic structure of the slot to maintain consistent, the same number of channels PCI-E slot, we are unable to determine from the appearance of the corresponding which version of the PCI-E specification. While the later slot is also compatible with low version of the device, and vice versa, but the rate to comply with "short board principle" and therefore compatible PCI-E slot is very strong.
Of course, PCI-E slot is not only one, according to specifications provided by the PCI-SIG, PCI-E slot has x1, x2, x4, x8, x12, x16 and x32 total of seven versions, corresponding to 1/2/4 / 8/12/16/32-channel, wherein the PCI-E x32 since the size of the problem, in some applications only in special occasions, the corresponding mass production is almost zero; PCI-E x12 servers are mainly used in the field, substantially It will appear on the consumer internet; PCI-E x2 are mainly used in internal expansion slots, rather than an interface, even if the motherboard is provided with a part of the interface, PCI-E x2 which are also substantially in the form of interface M.2 PCI-E slot form rather than appear. Therefore, the current mainstream motherboard PCI-E slot, basically focused on the PCI-E x1 / x4 / x8 / x16 are four here we take a look at the four slots in the end look like.
PCI-E x16 slots
Closest to the CPU's PCI-E x16 graphics card slot best suited installed
We start from the first slot PCI-E x16, PCI-E x16 slots full length 89mm, has a pin 164, into front and rear groups, located in front of the slot has a short pin 22, mainly for power supply, behind a slot 142 set longer, primarily for data transmission. Such design allows the PCI-E x16 slots have excellent compatibility can be backward compatible x1 / x4 / x8-level device, plus 16 channel which brings high-bandwidth, PCI-E x16 slots can be said to be fully PCI-E slot thereof in the consumer field in which a large majority for mounting the data throughput of products, such as video cards and RAID arrays.
Since the PCI-E x16 slot commonly used in graphics and therefore leads directly from the basic CPU, so that data exchange between the CPU and the graphics card can achieve the lowest latency, the performance of the system can be fully exploited.
PCI-E x8 slot
Compared to full-length PCI-E x8 slots 56mm, it has a pin 98, as compared to the PCI-E x16 mainly reduced to 76 data pins, power supply pins does not change. But we rarely see the real PCI-E x8 slots on the motherboard, because it usually appears in the form of PCI-E x16 slot, but only half of the data pins is effective, that is to say the actual bandwidth is only true PCI half -E x16 slot.
To install the graphics, PCI-E x8 slot will often appeared in the form of PCI-E x16 slot
In fact, the PCI-E x8 slot to make way x16 PCI-E is a reason, because PCI-E x8 graphics platform is to build a multi-born, in order to allow the use of PCI-E x16 graphics interface to successfully install the PCI-E x8 interfaces, which require their own natural "disguised" PCI-E x16 slots. Of course, there are some PCI-E x8 slot will open a small hole in the rear, so that the graphics card can be installed, but such interfaces often require customization, cost is not lower than the PCI-E x16 slots, but the impact on the visual is not enough, therefore direct use of PCI-E x16 slot PCI-E x8 slot to do naturally also makes sense.
So how do we distinguish between PCI-E x16 slot true PCI-E x16 slot and PCI-E x8 mode it? Experienced players can observe board layout, the latter half of the line connection is often not even stitch welding. But this is not the fastest way, in fact, in addition to the flagship platforms such as X299 offers a number of true PCI-E x16 slots, the mainstream platforms, including the newly released Z370 platform will only provide a real PCI- E x16 slot, is closest to the CPU of the piece. The second and third PCI-E x16 slot, the majority of PCI-E x8 x4 even level.
PCI-E x4 slot
PCI-E X4 slot length of 39mm, the same is based on PCI-E x16 slot on the data pins to reduce manner, mainly for the SSD PCI-E, or PCI-E is installed through riser M.2 SSD and so on. X4 PCI-E expansion slots are usually derived by the motherboard chip, but with the increase in the internal CPU channel number of the PCI-E, there are some high-end started to provide direct motherboard PCI-E X4 CPU socket for mounting PCI theoretically -E SSD can provide better performance, for example, there will be some performance improvement when compared to the use 4K QD motherboard chip PCI-E x4 slot.
Can not find PCI-E x4 slot? In fact, it appears in the form of M.2 interface
However, with PCI-E x8 slots are similar, PCI-E x4 slot is now rarely show people the real body, is more "rate of PCI-E x4 level of PCI-E x16 slots" form debut, or is extended to M.2 interface for installation M.2 SSD, M.2 M.2 wireless network card or other interface devices, and the rest is left to the expansion card PCI-E x1 slot is responsible.
PCI-E x1 slot
PCI-E x1 slot length is the shortest, only 25mm, compared to the PCI-E x16 slot, which data pins is greatly reduced to 14. The bandwidth of PCI-E x1 slot is usually provided by the motherboard chipset, more extensive product-oriented, independent network card, sound card independent, USB 3.0 / 3.1 expansion cards will be used in PCI-E x1 slot, you can even give via adapter cable PCI-E x1 slot card installed, or for mining multi-screen output.
Close-Mini PCI-E interface, consistent with the physical structure mSATA
Further PCI-E x1 slot there is still another aspect, generally referred to as Mini PCI-E slots, common in the Mini-ITX board, and notebook computers, wireless LAN to extend most, but because of its physical structure and on mSATA same slot, therefore, there are many motherboard BIOS will set or jumper so Mini PCI-E interface to PCI-E switch mode or SATA mode in order to achieve a dual effect.
But Mini PCI-E slots due to restrictions on bandwidth does not ultimately have been widely popular, and it mSATA interfaces in the face of attack M.2 interface choose a rapid retreat, and now its position and role have been M .2 interfaces substituted, basically farewell mainstream. Favorite hardware if you want to get free hardware welfare, we will pay attention to the popular ultra-small Colombian small series (micro letter: 9501417) activity on the 11th circle of friends posted it! Many hardware prizes welfare grants everyone!