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Wednesday, July 29, 2009

Mousepad



Mousepad




A mousepad is a surface for enhancing the usability of a computer mouse. Modern mousepads are typically made of lesser density rubber composites with fabric bonded to the upper surface. However, many other types of material have been used, including fabric, plastics, recycled rubber tires, silicone rubber, leather, glass, cork, wood, aluminum, stone and stainless steel. High-quality gaming mats are usually made from plastic, aluminum or high-tech fibers.




ATX MidTower Computer Case






A computer case (also known as a computer chassis, cabinet, tower, box, enclosure, housing or simply case) is the enclosure that contains the main components of a computer. A computer case is sometimes referred to metonymously as a CPU, referring to the primary component housed within the case; this was a more common term in the earlier days of home computers, when peripherals other than the motherboard were usually housed in their own separate cases.






ATX Midle Tower Computer Case

Monday, July 27, 2009

Wi-Fi Card


PCI Card WiFi





Wi-Fi is a trademark of the Wi-Fi Alliance for certified products based on the IEEE 802.11 standards. This certification warrants interoperability between different wireless devices.

In some countries (and in this article) the term Wi-Fi is often used by the public as a synonym for IEEE 802.11-wireless LAN (WLAN).

Not every IEEE 802.11 compliant device is certified by the Wi-Fi Alliance, which may be because of certification costs that must be paid for each certified device type. The lack of the Wi-Fi logo does not imply that a WLAN-device is incompatible to certified Wi-Fi-devices.

Wi-Fi is supported by most personal computer operating systems, many game consoles, laptops, smartphones, printers, and other peripherals.

DDR3 SDRAM



In electronic engineering, DDR3 SDRAM or double-data-rate three synchronous dynamic random access memory is a random access memory interface technology used for high bandwidth storage of the working data of a computer or other digital electronic devices. DDR3 is part of the SDRAM family of technologies and is one of the many DRAM (dynamic random access memory) implementations.

DDR3 SDRAM is an improvement over its predecessor, DDR2 SDRAM, and the two are not compatible. The primary benefit of DDR3 is the ability to transfer at twice the data rate of DDR2 (I/O at 8× the data rate of the memory cells it contains), thus enabling higher bus rates and higher peak rates than earlier memory technologies. There is no corresponding reduction in latency, as that is a feature of the DRAM array and not the interface.[citation needed] In addition, the DDR3 standard allows for chip capacities of 512 megabits to 8 gigabits, effectively enabling a maximum memory module size of 16 gigabytes.

With data being transferred 64 bits at a time per memory module, DDR3 SDRAM gives a transfer rate of (memory clock rate) × 4 (for bus clock multiplier) × 2 (for data rate) × 64 (number of bits transferred) / 8 (number of bits/byte). Thus with a memory clock frequency of 100 MHz, DDR3 SDRAM gives a maximum transfer rate of 6400 MB/s.

It should be emphasized that DDR3 is a DRAM interface specification; the actual DRAM arrays that store the data are the same as in any other type of DRAM, and have similar performance.

DDR2 SDRAM






DDR2 SDRAM is a double data rate synchronous dynamic random access memory interface. It supersedes the original DDR SDRAM specification and the two are not compatible. In addition to double pumping the data bus as in DDR SDRAM, (transferring data on the rising and falling edges of the bus clock signal), DDR2 employs an I/O buffer between the memory and the data bus so that the data bus can be run at the twice the speed of the memory clock. The two factors combine to achieve a total of 4 data transfers per memory clock cycle.

With data being transferred 64 bits at a time, DDR2 SDRAM gives a transfer rate of (memory clock rate) × 2 (for bus clock multiplier) × 2 (for dual rate) × 64 (number of bits transferred) / 8 (number of bits/byte). Thus with a memory clock frequency of 100 MHz, DDR2 SDRAM gives a maximum transfer rate of 3200 MB/s.

Since the memory clock runs at half the external data bus clock rate, DDR2 memory operating at the same external data bus clock rate as DDR will provide the same bandwidth but with higher latency, resulting in inferior performance. Alternatively, DDR2 memory operating at twice the external data bus clock rate as DDR may provide twice the bandwidth with the same latency (in nanoseconds). The best-rated DDR2 memory modules are at least twice as fast as the best-rated DDR memory modules.
 

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