pctechguide.com

  • Home
  • Guides
  • Tutorials
  • Articles
  • Reviews
  • Glossary
  • Contact

What is Level 1 (L1) Cache Memory?

The Level 1 cache, or primary cache, is on the CPU and is used for temporary storage of instructions and data organised in blocks of 32 bytes. Primary cache is the fastest form of storage. Because it’s built in to the chip with a zero wait-state (delay) interface to the processor’s execution unit, it is limited in size.

Level 1 cache is implemented using Static RAM (SRAM) and until recently was traditionally 16KB in size. SRAM uses two transistors per bit and can hold data without external assistance, for as long as power is supplied to the circuit. The second transistor controls the output of the first: a circuit known as a flip-flop – so-called because it has two stable states which it can flip between. This is contrasted to dynamic RAM (DRAM), which must be refreshed many times per second in order to hold its data contents.

SRAM is manufactured in a way rather similar to how processors are: highly integrated transistor patterns photo-etched into silicon. Each SRAM bit is comprised of between four and six transistors, which is why SRAM takes up much more space compared to DRAM, which uses only one (plus a capacitor). This, plus the fact that SRAM is also several times the cost of DRAM, explains why it is not used more extensively in PC systems.

Intel’s P55 MMX processor, launched at the start of 1997, was noteworthy for the increase in size of its Level 1 cache to 32KB. The AMD K6 and Cyrix M2 chips launched later that year upped the ante further by providing Level 1 caches of 64KB. 64Kb has remained the standard L1 cache size, though various multiple-core processors may utilise it differently.

For all L1 cache designs the control logic of the primary cache keeps the most frequently used data and code in the cache and updates external memory only when the CPU hands over control to other bus masters, or during direct memory access by peripherals such as optical drives and sound cards.

Some chipsets, such as the Pentium based Triton FX (and later), support a write back cache rather than a write through cache. Write through happens when a processor writes data simultaneously into cache and into main memory (to assure coherency). Write back occurs when the processor writes to the cache and then proceeds to the next instruction. The cache holds the write-back data and writes it into main memory when that data line in cache is to be replaced. Write back offers about 10% higher performance than write-through, but cache that has this function is more costly. A third type of write mode, write through with buffer, gives similar performance to write back.

  • What is Level 1 (L1) Cache Memory?
  • What is L2 (Level 2) cache memory?
  • RAM or Main Memory – PC / computer memory (DIMM, DRAM, SDRAM)
  • DRAM – Dynamic Random Access Memory
  • FPM DRAM
  • EDO (Extended Data Out) and BEDO (Burst Extended Data Out) DRAM
  • SDRAM
  • PC133 SDRAM
  • DDR SDRAM explained
  • DDR2 DRAM
  • Dual Channel DDR Memory
  • 1T SRAM
  • Direct DRAM
  • SIMMs
  • DIMM Memory
  • RIMMs Memory
  • Memory Presence Detection
  • Parity Memory
  • ECC Memory
  • Memory Upgrades
  • The Evolution of Memory
  • Flash Memory
  • Magnetic RAM

Filed Under: Computer Memory Tagged With: cache memory, L1 cache, Level 1 cache

Latest Articles

Win98 Installation Phase 2

After Setup Wizard is loaded the License Agreement is displayed. You must accept the License Agreement to continue. Setup prompts you to enter the Product Key. Type the Product Key in the spaces provided. The Product Key is located either on the Certificate of Authenticity (COA) or on … [Read More...]

Recover My Files Review

  This is PC Tech's number one choice for data recovery! As far as all around data recovery software goes, Recover My Files would have to be my absolute favorite. This product is great and I highly recommend it to anyone having any data issues. It has a very high success rate for data … [Read More...]

UTRAN

UTRAN Definition: UMTS Terrestrial Radio Access Network: the name of the WCDMA radio network in UMTS. … [Read More...]

Comments

  1. george says

    May 16, 2012 at 2:17 am

    very helpful contrast

The Importance of Data Security in Retail IoT

The Internet of Things (IoT) is transforming the retail industry by connecting physical stores with digital platforms, enabling smart inventory … [Read More...]

Review of Temu From Purchaser and Affiliate

Temu is a relatively new online shopping platform that has quickly gained popularity, especially among Gen Z shoppers. It is known for its ultra-cheap … [Read More...]

Avoid Data Breaches Caused by Weak Passwords

Weak passwords are a common cause of data breaches and security vulnerabilities. Weak passwords make it easier for cybercriminals to gain unauthorized … [Read More...]

20 Cool Pictures of Silicon Valley You’re Sure to Love

Silicon Valley, a name synonymous with innovation and technological prowess, is a place where dreams and ideas come to life. Nestled in the heart of … [Read More...]

13 Funky Images of Laptops

In our digital age, laptops have become our faithful companions, indispensable tools for work, leisure, and everything in between. They've evolved … [Read More...]

20 Spectacular Images About Artificial Intelligence

In the age of artificial intelligence, the very fabric of our world is undergoing a profound transformation. From enhancing everyday tasks to … [Read More...]

Guides

  • Computer Communications
  • Mobile Computing
  • PC Components
  • PC Data Storage
  • PC Input-Output
  • PC Multimedia
  • Processors (CPUs)

Recent Posts

Junk Temp File Cleaning

Video Covering Junk Temp File Cleaning - Part of our Fix Slow Computer tutorial found onĀ  … [Read More...]

ADSL2 Speed and wiki – History of ADSL2

Even before designs based on the first generation standards (ITU G.992.1 and G.992.2) had been perfected, the ITU had been … [Read More...]

Be Productive With Your iPads With Keyboard Cases

When it comes to portability, lightness and convenience, the tablets are the best in these categories. However, if you are on the productive side, the … [Read More...]

[footer_backtotop]

Copyright © 2023 About | Privacy | Contact Information | Wrtie For Us | Disclaimer | Copyright License | Authors