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Cache Memory

Cache memory works by saving parts of the main memory, which are frequently visited, in its own memory area. By doing this it will have stored parts of a program you may be frequently accessing and so eliminate the requirement of continually reloading that part from the hard drive when you want to re-use it.

The cache memory area also uses ultra-fast DIL RAM memory chip devices which give the impression of almost instant access to the frequently used parts of a program. The result of all this a large increase in the speed of the computer. For example, a 486DX4 100Mhz CPU without secondary cache memory will perform more slowly than a machine with cache memory running at half the clock speed.

In the past some computer shops have tended to sell their 486 'mother boards' about £10, or £15 cheaper without the cache memory on board. If you intend to upgrade to a faster processor always insist on as much cache secondary memory as you can afford. After all what is the use of upgrading from, for example a 486SX 33Mhz to a 486DX 100Mhz CPU if lack of cache memory means that you increase in speed is going to be minimal.
On 486 mother boards cache secondary memory can be either 128Mb, or 256Mb in size.

If you are going to upgrade to a Pentium P75 or P100 you will find that the practice of fitting no cache memory is rare. All Pentium boards now come fitted with either 128Mb or 256Mb of cache memory. But always check.