Tag RAM

The area in an L2 cache that identifies which data from main memory is currently stored in each cache line. The actual data is stored in a different part of the cache, called the data store. The values stored in the tag RAM determine whether a cache lookup results in a hit or a miss.

The size of the data store determines how much data the cache can hold at any one time. The size of the tag RAM determines what range of main memory can be cached. Many modern PCs, for example, are configured with a 256K L2 cache and tag RAM that is 8 bits wide. This is sufficient for caching up to 64 MB of main memory. If you add additional main memory, however, it won’t be cached unless you also expand tag RAM. Some motherboards allow you to add additional tag RAM chips for this purpose but many do not.

For Pentium Pro and Pentium II microprocessors, the tag RAM is integrated in the chipset. Pentium Pros have an integrated L2 cache capable of caching up to 4 GB of main memory. Pentium IIs use a SEC daughtercard for L2 caches and can cache up to 512 MB.

Webopedia Staff
Webopedia Staff
Since 1995, more than 100 tech experts and researchers have kept Webopedia’s definitions, articles, and study guides up to date. For more information on current editorial staff, please visit our About page.

Top Articles

The Complete List of 1500+ Common Text Abbreviations & Acronyms

Text Abbreviations reviewed by Web Webster   From A3 to ZZZ we list 1,559 SMS, online chat, and text abbreviations to help you translate and understand...

How to Create a Website Shortcut on Your Desktop

Website Shortcut on Your Desktop reviewed by Web Webster   This Webopedia guide will show you how to create a website shortcut on your desktop using...

Windows Operating System History & Versions

The Windows operating system (Windows OS) refers to a family of operating systems developed by Microsoft Corporation. We look at the history of Windows...

First to Fifth Generations of Computers

Reviewed by Web Webster   Learn about each of the 5 generations of computers and major technology developments that have led to the computing devices that...

Heuristic Definition and Meaning

Heuristic, pronounced hyoo-ri-stihk, is a Greek term for individually finding or discovering. In...

Hackerspace Definition & Meaning

What is a hackerspace? A hackerspace, also known as a hacklab, incubator, or hackspace,...

Random Access Memory (RAM)...

Random Access Memory (RAM) reviewed by Web Webster   Random Access Memory (RAM) is a...