SDHC Memory Card

SDHC (Secure Digital High Capacity) Memory Card
Secure Digital (SD) is a non-volatile memory card format developed by Matsushita, SanDisk, and Toshiba for use in portable devices. Today it is widely used in digital cameras, digital camcorders, handheld computers, PDAs, media players, mobile phones, GPS receivers, and video games. Standard SD card capacities range from 1 MB to 4 GB. The capacity range for high capacity SDHC cards overlap, beginning at 4 GB but reaching as high as 32 GB as of mid-2009. The SDXC (eXtended Capacity), a new specification announced at the 2009 Consumer Electronics Show, will allow for up to 2 TB capacity cards.

What is the SDHC Memory Card?
At the 2006 International CES, the SD Card Association (SDA) announced their establishment of the SD Specification Version 2.0 for the SDHC (Secure Digital High Capacity); making way for the SDHC to be the next generation SD Card. Engineered to meet higher memory capacities, the SDHC will meet the higher requirements in a new generation of technology that enables SD cards to reach higher capacities of 4GB to 32GB. New electronic devices that will utilize SDHC memory cards include audio/video and telecommunications gadgets such as digital cameras, camcorders, mobile phones, computers, PDAs, plasma televisions, and many more.

The growing demand for high-capacity flash memory springs partially from the increasing use of high-definition video and high-resolution digital photography. SDHC cards meet the challenge of these demanding products not only by providing ample storage but also by introducing a new feature: classifications of data transfer speed (DTS). Consumers can get the best performance value out of their digital products by using flash memory cards that support the device's highest standards for data transfer speed. The SDHC specification 2.00 calls for cards to be classified according to the minimal sustained DTS as follows:
• Class 2: minimum sustained DTS of 2MB/sec
• Class 4: minimum sustained DTS of 4MB/sec
• Class 6: minimum sustained DTS of 6MB/sec

What Speed Do You Need?
To help you find the right speed, SD/SDHC cards are broken down into four classes: Class 2, Class 4, Class 6 and Class 10. Class 2 cards offer a minimum sustained data rate of 2 megabytes per second (MBps), Class 4 of 4MBps and Class 6 of 6MBps and Class 10 of 10MBps. Depending on which manufacturer is selling the card, the speed class will either be prominently displayed or buried in the specs. Either way, look for it.

The benefits of SDHC memory cards extend beyond mere matters of size. Along with their tiny physical profile, there is also the fact that they hold a remarkable amount of memory and have blazingly fast data transfer speeds. While USB-based flash memory cards may be faster and offer more memory, they are much larger. Additionally, SDHC memory cards have an updated file storage system that allows them to store data more efficiently than SD memory cards.



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How to Buy Computer Memory

Computer Memory (RAM) is one of the important devices in your computer. Before you buy a new RAM, knowing about RAM will give you some information to buy the right one to your computer.

What is Computer Memory?
A computer is constantly processing information. Whether you are just turning your PC on, maintaining its functionality, or running an application, it needs to move data along where it needs to go. The reason you need memory is to help your computer out by giving it a temporary location called “random access memory” (or RAM) to store information so it can process it more efficiently. If your computer did not have any memory and had to access the hard drive every time it needed data, your computer would run extremely slow.

Computer Memory Types:
• SDRAM (Synchronous DRAM)
Almost all systems used to ship with 3.3 volt, 168-pin SDRAM DIMMs. SDRAM is not an extension of older EDO DRAM but a new type of DRAM altogether. SDRAM started out running at 66 MHz, while older fast page mode DRAM and EDO max out at 50 MHz. SDRAM is able to scale to 133 MHz (PC133) officially, and unofficially up to 180MHz or higher. As processors get faster, new generations of memory such as DDR and RDRAM are required to get proper performance.
• DDR (Double Data Rate SDRAM)
DDR basically doubles the rate of data transfer of standard SDRAM by transferring data on the up and down tick of a clock cycle. DDR memory operating at 333MHz actually operates at 166MHz * 2 (aka PC333 / PC2700) or 133MHz*2 (PC266 / PC2100). DDR is a 2.5 volt technology that uses 184 pins in its DIMMs. It is incompatible with SDRAM physically, but uses a similar parallel bus, making it easier to implement than RDRAM, which is a different technology.
• Rambus DRAM (RDRAM)
Despite it's higher price, Intel has given RDRAM it's blessing for the consumer market, and it will be the sole choice of memory for Intel's Pentium 4. RDRAM is a serial memory technology that arrived in three flavors, PC600, PC700, and PC800. PC800 RDRAM has double the maximum throughput of old PC100 SDRAM, but a higher latency. RDRAM designs with multiple channels, such as those in Pentium 4 motherboards, are currently at the top of the heap in memory throughput, especially when paired with PC1066 RDRAM memory.
• DIMMs vs. RIMMs
DRAM comes in two major form factors: DIMMs and RIMMS. DIMMs are 64-bit components, but if used in a motherboard with a dual-channel configuration (like with an Nvidia nForce chipset) you must pair them to get maximum performance. So far there aren't many DDR chipset that use dual-channels. Typically, if you want to add 512 MB of DIMM memory to your machine, you just pop in a 512 MB DIMM if you've got an available slot. DIMMs for SDRAM and DDR are different, and not physically compatible. SDRAM DIMMs have 168-pins and run at 3.3 volts, while DDR DIMMs have 184-pins and run at 2.5 volts. RIMMs use only a 16-bit interface but run at higher speeds than DDR. To get maximum performance, Intel RDRAM chipsets require the use of RIMMs in pairs over a dual-channel 32-bit interface. You have to plan more when upgrading and purchasing RDRAM.

When to Buy More Memory
there are usually five scenarios under which you'd buy memory for your computer:
• When upgrading your operating system
• When installing new applications
• When installing multimedia cards
• When adding computer peripherals
• When your hard disk starts 'chugging'

Finding what type of RAM your computer:
You may not always find what type of RAM your computer has by looking in my computer on the general tab. You will need to open your computer case. It will depend on what type of case you have as to how to go about it.

Before doing anything, disconnect your computer from the power. On the back of the case you will find several screws, remove the ones holding the side on. Then remove that panel. Look inside on the motherboard for longish side-by-side slots. They could be three to five inches long. Ram is normally a small flat piece with a brass looking edge that fits into the long slot.
Look on the side of the RAM; you may need to use a torch to read the writing. This will tell you what type and size of ram is in your computer.

You can also find out what type of RAM you have by restarting your computer and reading the information as the computer loads.

Now you know about Computer Memory and Ready to buy the new RAM :)



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