Learn about the technologies behind the Internet with The TCP/IP Guide!|
NOTE: Using robot software to mass-download the site degrades the server and is prohibited. See here for more.
Find The PC Guide helpful? Please consider a donation to The PC Guide Tip Jar. Visa/MC/Paypal accepted.
|View over 750 of my fine art photos any time for free at DesktopScenes.com!|
The oldest and slowest type of cache timing is asynchronous cache. Asynchronous means that transfers are not tied to the system clock. A request is sent to the cache, and the cache responds, and this happens independently of what the system clock (on the memory bus) is doing. This is similar to how most system memory works; your typical FPM or EDO memory is also asynchronous (and relatively slow, for this reason.)
Because asynchronous cache is not tied to the system clock, it can have problems dealing with faster clock speeds. At slow speeds like 33 MHz it is capable of 2-1-1-1 timing (which is very good) but at speeds like 60 or 66 MHz as used in modern Pentium class PCs it drops down to 3-2-2-2 (which is pretty bad.) For this reason, asynchronous cache is commonly found on 486 class motherboards but is not generally used on Pentium or later class machines.
Next: Synchronous Burst Cache