One of the main reasons for the triumph of the PC is its modular structure. This means that desktop PCs and notebooks are made up of variable components, but they communicate via precisely defined and standardized interfaces.
PCI Express 3.0: Port instead of Bus
Over time, however, a real jungle has formed at these vital interfaces. We bring light to this interface light and take a closer look at the latest and fastest representatives of all types.
Higher data rates with 32 lanes
PCI Express is the most important internal interface on the mainboard for communicating with graphics and expansion cards. Unlike PCI, PCI Express is not a parallel bus system, but works with lanes, that is, serial, bidirectional point-to-point connections. The advantage over a parallel bus system like PCI is that individual devices do not have to share the available bandwidth on the bus, but each device is connected to the full data rate.
PCIe 4.0 already in work
In the first PCI Express version 1.0a, the transfer rate per lane was 250 Mbyte / s - already significantly more than the legacy PCI standard with 133 Mbyte / s. With PCIe 2.0 the transfer rate was basically doubled, the new PCIe 3.0 standard brings an increase by a further 60 percent. This is equivalent to a bandwidth of about one gigabyte / s since PCIe 3.0 operates with a lower overhead.
Downward Compatible
For higher data rates, up to 32 lanes can be combined with PCI Express. In practice, however, only a maximum of 16 lanes are used in parallel, primarily for connecting graphics cards.
The number of available PCI Express lanes on a motherboard depends on the chipset or the processor. Intel has integrated a PCIe controller with the current processors on the CPU die. The top model Sandy Bridge Extreme provides here even 40 PCIe 3.0 lanes. Another PCIe 2.0 controller with up to eight lanes is included in the chipset. It is used to connect components on the mainboard, such as Ethernet controllers, additional SATA controllers, or Firewire chips.
The integrated controller provides 24 lanes for the A series of Intel's continuous AMD. The new Trinity APU only supports PCI Express 2.0, even though AMD itself produces graphics chips with a PCIe 3.0 interface. In practice, PCIe 3.0's performance gains are still low on current cards, and PCIe 2.0 is still good .
Nevertheless, the PCI Special Interest Group (PCI-SIG) is already working on a specification for the fourth generation of PCI Express. With PCIe 4.0 the transfer rate should be doubled again. However, the specification is probably not finalized before the end of 2017.
With PCI Express, there are different sockets and card formats with different PCI Express lanes. In this case, cards with an x1, x4 or x8 connection fit, this number gives the number of lanes and thus the possible data transfer rate, physically into any PCIe slot of any length - the detection takes place automatically.
The number of PCI Express lanes connected to a slot can also be lower than the number of ports a slot could provide due to its length. Here you have to inform yourself in the mainboard manual, so as not to inadvertently insert the graphics card into a supposed x16 slot, which is actually only connected with four lanes.
Cards and mainboards with different PCIe standards are largely compatible with each other. There can be problems only with the use of modern graphics cards with PCIe 2.1 or 3.0 interface on old motherboards with PCIe 1.0 sockets, but these can usually be corrected by a BIOS update. But in principle, the use of a brand new card in an eight-year-old PC anyway is not useful.
For boards with more than one PCIe x16 slot and a PCI Express controller that can handle less than 32 lanes, the 16 lanes are automatically split into the slots when using two or more graphics cards. A special feature of the graphics cards intended for graphics cards lies in the voltage supply. They can deliver up to 75 watts, otherwise the PCI Express specification is 25 watts.
The dominant interface for the connection of drives is now serial rather than parallel, so only one drive is connected per port. SATA comes through the serial transmission with slim, four-core cables, which in desktop PCs barely interfere with the air current in contrast to the wide flat-band cables with parallel ATA.
SATA 3.1: Slim and fast
In addition, SATA supports hotplugging, ie the device connection during operation, and the interface provides the high data rates necessary for SSDs. This is especially true for the current third version of the Serial ATA protocol with transfer rates of up to six Gbps. The latest SATA revisions 3.1 bring changes to the mSATA interface for notebooks and netbooks, which makes the use of extremely compact SSDs possible.
To ensure that new SSDs with SATA 3.0 support also bring their full performance, a suitable SATA controller must be available on the other side. The current Intel chipsets series 6 and 7 support two SATA 3.0 interfaces and four SATA 2.0 interfaces with 3 GBit / s. AMD, on the other hand, offers an end-to-end SATA 3.0 support. For motherboards without SATA 3.0 support, however, you can also upgrade a controller to a PCIe card. Some new Serial Attached SCSI controllers also support SATA drives.
SATA controller for full performance
Finally, eSATA also has its own standard for external drives, in which a SATA more solid connector is defined. In contrast to USB, however, a conventional eSATA connector requires a separate power supply. Some new notebooks have an eSATAp port, which provides the necessary power via USB. In addition to the rare eSATAp drives that drive their operating voltage via USB, it can also be used with conventional eSATA drives and USB devices.
Already today SSDs with PCI Express interface are on the market, such as OCZ and, more recently, Intel. With SATA Express, a new standard is now being developed which uses PCI Express 3.0 for data transmission. The plug-in connectors provided for this purpose are intended to support both the new SATA-Express connector and conventional SATA connectors.
The universal serial bus is the egg-laying wool milk under the interfaces: it can be connected to mice, keyboards, printers, scanners, memory sticks, all kinds of drives and also devices such as TV receivers, sound boxes, headsets. In addition to the large USB port, Mini and Micro USB are still available. They are used on smartphones, tablets and some ultrabooks.
ESATA for external drives
USB 3.0: The Universalist
Thunderbolt: The Future
Ways to monitor: VGA, HDMI & Co
With USB 3.0 the interface is also fast enough for external SSDs, in SuperSpeed mode a net data rate of 300 MB / s is reached. USB 2.0 with 35 MB / s does not even for fast conventional HDDs out. With USB 3.0 the real achievable performance depends on the controller and its connection. One advantage of USB 3.0 is the cable length of up to three meters. ESATA is limited to two meters.
Last year, Thunderbolt introduced another external high-speed interface. In the first evolutionary stage, the serial Thunderbolt interface works with a bidirectional transmission rate of 10 Gbit / s, which is significantly faster than USB 3.0.
Thunderbolt was only used by Apple, but now it is also found in Windows computers. Asus, MSI and Gigabyte have developed mainboards with Thunderbolt port, Acer is launching an Ultrabook with the new Intel interface with the Aspire S5, the Asus G75V already has the new interface.
Six devices in series connection
For the transmission, copper cables with a maximum length of three meters are used, with optical cables later up to 10 meters possible. In addition, up to six external Thunderbolt devices can be connected in a chain, provided that they have their own power supply. Devices that are powered by the Thunderbolt cable can only form the end of the chain.
For the connection, Intel uses a modified Mini-DisplayPort socket, which also transmits image and audio information. Thunderbolt is therefore also suitable for monitors, which serve as a docking station at the same time. An example is the Apple Thunderbolt Display.
Technically, Thunderbolt USB 3.0 is clearly superior. But the new interface currently has a crucial disadvantage: it is expensive. This applies not only to the Thunderbolt chip from Intel, but also to the cables. The high data rate requires active transceiver chips in the connectors, which are responsible for a price of more than 40 euros.
For the connection of a flat screen, digital interfaces such as DVI, HDMI or DisplayPort are now setting the tone. Because here the image quality is better, since the superfluous conversion from digital to analog and back again to digital falls away.
Modern graphics interfaces such as HDMI or DisplayPort not only transmit digital image information from the computer to the monitor, but also audio data. Via HDMI 1.4a it is also possible to connect TV sets with a 3D display, to play around 3D Blu-rays. AMD Radeon cards of the 7000 series already officially support the 4K resolution with 4096 x 2160 pixels, Nvidia only unofficial.
DisplayPort is a license-free competition standard for HDMI. It supports HDCP's standard HDMI protection since version 1.1, and the new version 1.2 adds 3D and 4K support as well as the series connection of several displays as features.
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