There are also PCI-X slots on some workstations or servers.
PCI-X is an extended architecture of PCI bus. The frequency of PCI-X is not fixed like PCI, but can change with the change of equipment. PCI-X can support 66, 100 and 133 MHz, and may provide more frequency support in the future.
1) ISA slot
ISA slot is an expansion slot based on ISA bus (industrial standard architecture), which is generally black in color, longer than PCI interface slot and located at the bottom of the motherboard. Its working frequency is about 8MHz, which is 16 bit slot, and its maximum transmission rate is 8MB/ s. Expansion cards such as graphics cards, sound cards, network cards and so-called multi-function interface cards can be inserted. Its disadvantage is that the CPU resource occupation is too high and the data transmission bandwidth is too small, so it is a slot interface that has been eliminated. ISA slots can be seen on many old motherboards at present. Now, ISA slots are almost invisible on the new motherboard, but there are exceptions. Some brands of 845E motherboards and even 875P motherboards also have ISA slots, presumably to meet the needs of some special users.
2) PCI slot
PCI slot is an expansion slot based on PCI local bus (Pedpherd Component Interconnect), which is generally ivory in color and located below AGP slot and above ISA slot on motherboard. Its bit width is 32 bits or 64 bits, its working frequency is 33MHz, and its maximum data transmission rate is 133 MB/ s (32 bits) and 266 MB/ s (64 bits). Card card, sound card, network card, built-in modem, built-in ADSL modem, USB 2.0 card, IEEE 1394 card, IDE interface card, RAID card, TV card, video capture card and other expansion cards. PCI slot is the main expansion slot of motherboard. By plugging in different expansion cards, almost all the external functions that can be realized by computers at present can be obtained.
3) AGP slot
AGP(Accelerated Graphics Port) is developed on the basis of PCI bus, which is mainly optimized for graphic display and specially used for graphic display cards. The AGP standard has also developed for several years, from the initial AGP 1.0 and AGP 2.0 to the present AGP 3.0. According to the speed, it mainly experienced AGP 1X, AGP 2X, AGP 4X and AGP PRO. At present, the latest movie version is AGP 3.0, namely AGP 8X. The transmission rate of AGP 8X can reach 2. 1GB/s, which is twice that of AGP 4X. AGP slots are usually brown. Another thing to note is that it is not in the same horizontal position as PCI and ISA slots, but is built-in, which makes it impossible to insert PCI and ISA cards. Of course, the AGP slot structure is completely different from PCI and ISA, so it is impossible to insert it wrong.
4) AMR slot
AMR(Audio Modem Riser) specification, which is an open industrial standard initiated by Intel in 1998, calls on other related manufacturers to make the conversion circuit of digital signal and analog signal on a circuit card. Because before this, the analog signals and digital signals on the motherboard would interfere with each other when they were together. AMR specification is to integrate the functions of sound card and modem on the motherboard, and at the same time isolate digital signals from analog signals to avoid mutual interference. This not only reduces the cost, but also solves some functional limitations of sound card and Modem subsystem. Because the control circuit and digital circuit are easy to be integrated into the chipset or motherboard, the interface circuit and analog circuit are difficult to be integrated into the motherboard for some reasons (such as electromagnetic interference and different electrical interfaces). Therefore, Intel Corporation specially developed AMR slots, with the purpose of transferring analog circuits and I/O interface circuits to separate AMR cards and integrating other components into the chipset on the motherboard. AMR slot is generally located near the PCI slot (white) on the motherboard, which is relatively short (only about 5 cm) and brown in appearance. You can insert an AMR sound card or an AMR modem card. But most integrated motherboards are integrated with AC'97 sound chip, so AMR slot is mainly used with AMR modem. However, because AMR Modem card takes up more CPU resources than the general built-in soft Modem card, the use effect is not ideal, and the price is not much better than the built-in Modem card, so AMR slot is quickly replaced by CNR.
5) CNR slot
In order to meet the needs of the development of broadband network technology and make up for the deficiency of AMR specification design, Intel timely introduced CNR (communication network riser) standard. Compared with AMR specification, the new CNR standard has a wider application range. It can not only connect a special CNR modem, but also use a special home telephone network (home PNA), and it conforms to the plug-and-play function of PC 2000 standard. Most importantly, it adds support for 10/ 100MB LAN function, and provides support for AC'97 compatible AC-Link, SMBus interface and USB( 1. 1 or 2.0) interface. In addition, CNR standard supports motherboards with ATX, micro ATX and Flex ATX specifications, but does not support motherboards with NLX format (AMR support). From the appearance, CNR slot and AMR slot are similar (also brown), but the former is slightly longer and the number of pins is different, so AMR slot and CNR slot are not compatible. The card types supported by CNR include audio CNR, modem CNR, USB Hub CNR, home PNA CNR, LAN CNR, etc. However, the market support for CNR is not enough, and the corresponding products are few, so most CNR slots on the motherboard have become useless furnishings.
6) ACR slot
ACR stands for advanced communication riser. In order to compete with Intel's AMR, VIA, together with world famous manufacturers such as AMD, 3Com, Lucent, Motorola, NVIDIA and Texas Instruments, launched an open industry technical standard in June 2006. Its purpose is also to expand the function of AMR in network communication. ACR is not only fully compatible with AMR specification, but also defines a perfect standard interface for network and communication. ACR card can provide modem, LAN (local area network), home PNA, broadband network (ADSL, Cable Modem), wireless network, multi-channel sound processing and other functions. The ACR slot is mainly designed to be placed in the original ISA slot. ACR slot adopts 120 pin design, which is compatible with ordinary PCI slot, but the direction is just the opposite, ensuring that the two cards will not be confused. Although both ACR and CNR standards contain all the contents of AMR standards, they are incompatible or even mutually exclusive (which is also the evil result of market competition). The most obvious difference between them is that CNR abandoned the original infrastructure, that is, gave up compatibility with AMR standard, while ACR standard added many new functions while retaining compatibility with AMR. However, like CNR, the market does not support ACR enough, and there are few corresponding products, so most ACR slots on motherboards have become useless furnishings.
7) PCI Express slot
PCI-Express is the latest bus and interface standard. Its original name is "3GIO", which was put forward by Intel Corporation. Obviously, what Intel means is that it represents the next generation I/O interface standard. It was renamed "PCI-Express" after being certified and published by PCI-SIG(PCI Special Interest Organization). This new standard will completely replace the existing PCI and AGP, and finally realize the unification of bus standards. Its main advantage is its high data transmission rate, which can reach above 10GB/s at present, and its development potential is considerable. PCI Express also has many specifications, from PCI Express 1X to PCI Express 16X, which can meet the needs of low-speed equipment and high-speed equipment at present and in the future. Intel's i9 15 and i925 series chipsets can support PCI Express. Of course, it will take a long time to completely replace PCI and AGP, just as there will be a transitional process when PCI replaces ISA.
When purchasing motherboard products, the type and quantity of expansion slots are important indicators to determine the purchase. There are many types and sufficient expansion slots, which means there will be enough upgrades and equipment expansion in the future. On the contrary, there will be huge obstacles in the future upgrade and equipment expansion. This is especially important for beginners. For example, I am not satisfied with the game performance of the integrated motherboard, and I want to upgrade to an independent graphics card, only to find that there is no AGP slot on the motherboard; I want to add a video capture card, but I found that all the PCI slots used are full, and so on. However, the more expansion slots, the better. Too many slots will increase the cost of the motherboard and increase the purchase cost of users, while too many slots will not affect many users. For example, an office computer that only needs to do word processing and surf the Internet, equipped with six PCI slots and a discrete graphics card, is a typical waste of resources. This kind of computer can fully meet the use requirements only by using the integrated micro ATX motherboard. Therefore, in the purchase of specific products, we should choose according to our own needs, and the one that suits us is the best.