Improve Your (PC’s) Memory
Casual computer users are often confused by the concept of memory versus storage capacity. All the programs, data files, pictures, and music you load onto your computer are permanently retained on your hard drive, a device designed for permanent storage where space is typically measured in gigabytes - billions of bytes of storage.
Memory, on the other hand, is fleeting – but you already knew that, didn’t you? System memory, more often measured in megabytes (millions of bytes), is where the computer holds current programs and data that are in use. As long as electrical power is supplied to the machine, memory holds its data. But power off the system, and nearly everything held in memory is gone.
You actually have several different types of memory in your computer. A special type of very fast, very expensive memory is attached to your central processor, the main computer chip in the machine. This type is memory is called SRAM, an acronym for Static Random Access Memory. SRAM is made of highly-integrated transistor patterns photo-etched into silicon. It is most often referred to as level one or level two cache. SRAM holds its data without ‘external refresh’, the capability that most distinguishes it from DRAM, or dynamic RAM.
A second type of memory in your machine is ROM, or Read Only Memory. This is memory that is capable of being read but not written to, except in certain cases. The most common use of ROM is the system’s BIOS chip. When the computer starts, its system memory is empty. Something needs to tell it what to do to start up. That something is the BIOS chip. The memory in the BIOS is more or less permanent and does not lose its data when disconnected from power. Technically, the BIOS is an EEPROM chip: electrically erasable programmable read only memory, meaning you can in fact interact with it and make changes to it.
184-pin DDR 400 (PC3200) SDRAM
System memory is a type of DRAM, or dynamic random access memory. If you want to feel superior to your computer, read this. The DRAM in the computer is constructed with capacitors that lose their memory contents thousands of time per second, and must be continuously refreshed, electrically, to retain the data within them. I, on the other hand, can often go several seconds at a time, often even minutes, without forgetting something.
You’ll see several different terms used to describe the types of system memory: SDRAM (synchronous DRAM), DDR-SDRAM (double data rate SDRAM), DDR2-SDRAM, and RDRAM (Rambus DRAM) to name a few. If that’s not enough mumbo-jumbo for you, memory comes packaged on different types of modules or circuit boards which may go by names like SIMM (single in-line memory module), DIMM (dual inline memory module), and SODIMM (small outline dual inline memory module, usually used in laptops.) The module may have 72 pins (old memory style), 168 pins, 184 pins, or 200 pins. The form of memory module used must match the type of memory connector on the system motherboard (main circuit board.) You may also run into the term Dim Sum. This has nothing to do with memory, and merely means you have wandered into a Chinese restaurant.
184-pin RDRAM PC800
Next to the speed of your CPU, no greater factor affects performance than the amount of system memory in your computer. An increase in memory can often be the least expensive and most effective upgrade you can make. How much you need is dependent on your operating system and the tasks you ask your machine to perform. Space does not permit a full run-down of the possibilities. However, let’s assume your operating system is Windows XP. I’ve seen many machines sold with only 128 megabytes of memory just to meet a price point in the market, but an XP machine with only 128MB of RAM is essentially crippled. I would set 256MB of RAM as the real minimum for running a reasonable XP setup. If you want more zip to run more intensive applications, 512MB should be on board, and a full gigabyte of memory is not unreasonable. The newest version of Windows, called Vista, is said to want a minimum of 512MB of memory, with a full gigabyte preferred.
168-pin PC133 SDRAM
To see how much memory is in your PC, right click on ‘My Computer’ and then left click on ‘Properties’. You’ll get a screen that will tell you the speed of your processor and how much memory is installed. Typically it is some multiple of 128. If you see an odd number like 224MB, it means your video sub-system does not have its own dedicated memory, and is sharing system memory.
200-pin DDR2 SODIMM (for laptop)
If you want to add memory but don’t know what kind to buy, several on-line vendors have excellent memory configurators that will walk you through finding the right type of memory for your system. At www.crucial.com you’ll find a downloadable memory configurator which will probe your system and tell you exactly what type of memory module you need. (And you thought you had to be abducted by aliens to have your system probed!) My favorite place for buying memory is www.kahlon.com. They are far less expensive than Crucial or Kingston or several other OEM manufacturers, and I only recently ran into my first problem with compatibility or reliability. Installing the new module seldom involves more than powering off the system, removing the case, lining up the module with the open memory slot, and pressing into place until the retainer clips engage.
I wish improving my own memory were as cheap and easy.
Big Horn Ram