Forest Software

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Upgrading Your Computer Memory

There has never been a better time to increase memory capacity. When you think that the increased use of memory-intensive applications such as video editing has already caused 1 Gb configurations to be the standard specification on many new machines and Microsoft's forthcoming Windows Vista operating system release is bound to increase the minimum amount of RAM required with reports saying the 2Gb is the ideal memory size..

Though maximising the amount of memory on new systems is as easy as choosing a standard system there are several questions you should ask when upgrading existing systems such as :-

  • What memory speed and type of memory does the motherboard support?
  • How much RAM does a particular system support?
  • What issues might affect compatibility?
  • Is there any reason to buy name brand RAM?


Memory UpgradesRAM is normally rated at its highest tested stable speed, first of all by the chip manufacturer in cycle time (measured in nanoseconds, or ns) and then by the module producer in frequency (megahertz, or MHz).

By design, DRAM maintains its data only as long as a charge is applied to the cells, so there is no maximum cycle time. For example, 133 MHz SDRAM could operate at 133 MHz, 100 MHz, 66 MHz, or even at speeds of less than 1 MHz, depending on how quickly the system accesses it. This allows a wide range of compatibility for higher speed modules in older systems; it has become common practice for RAM manufacturers to re-label faster RAM at slower speeds whenever the slower RAM ceases production.

Double Data Rate (DDR) technology allows data to be transmitted twice per clock cycle, so DDR SDRAM with a 200 MHz clock rate actually has a 400 MHz data rate, and is referred to as DDR400. The naming convention for finished modules has become its bandwidth, with each module providing 64 data connections for 8 Bytes of data per transfer. A 400 MHz data rate multiplied by 8 Bytes per transfer provides 3,200 MB/s bandwidth, hence the name PC3200.

Previously, memory types were rated by their speed or data rate alone, with PC133 SDRAM specified to support at least 133 MHz operation at 100% stability, and PC800 RDRAM specified to operate at 800 MHz data rate.

In modern systems, you'll usually encounter a memory capacity limit of between 1 Gb to 4 Gb, this depends on both the chipset and the BIOS. However, operating systems also have limits, Windows 95, 98 and ME supported only 512 MB. Windows 2000 and XP will in theory support up to 4 Gb, but will often limit access to 3 GB, making 2 Gb the best solution for many upgraders.

By using the box below you will be able to check the amount of memory in your PC and find out how much more it will take.



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