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What is the difference between L1, L2 and L3 Cache Memory ?

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تم إضافة السؤال من قبل Home Front , فني تكنولوجيا المعلومات , multimedia Center Systems
تاريخ النشر: 2016/08/01
Ghada Eweda
من قبل Ghada Eweda , Medical sales hospital representative , Pfizer pharmaceutical Plc.

 Basically, L1, L2 and L3 caches are different memory pools similar to the RAM in a computer. They were built in to decrease the time taken to access data by the processor. This time taken is called latency. The architecture they are built with also differs considerably. For eg. the L1 cache is built using larger transistors and wider metal tracks, trading off space and power for speed. The higher level caches are more tightly packed and use smaller transistors.

    There are other complexities to the story also like the fact that other clerks (processors) can open and search(has access to) the cupboard (L3 cache).

    The access times of data in these memories are usually of the order of nanoseconds and do not really make a difference to the average user. But for scientists/programmers that develop/use programs that process a lot of data, it matters. They make a huge difference of the order of days or months even!

L1 (Level 1), L2, L3 cache are some specialized memory which work hand in hand to improve computer performance. When a request is made to the system, CPU has some set of instructions to execute, which it fetches from the RAM. Thus to cut down delay, CPU maintains a cache with some data which it anticipates it will be needed.(L1) Level 1 Cache(2KB - 64KB) - Instructions are first searched in this cache. L1 cache very small in comparison to others, thus making it faster than the rest.(L2) Level 2 Cache(256KB - 512KB) - If the instructions are not present in the L1 cache then it looks in the L2 cache, which is a slightly larger pool of cache, thus accompanied by some latency.(L3) Level 3 Cache (1MB -8MB) - With each cache miss, it proceeds to the next level cache. This is the largest among the all the cache, even though it is slower, its still faster than the RAM.Now you know what cache is and what different level of cache are.And that 6MB value of the L3 Cache in your Intel 4700MQ microprocessor is actually the memory size of that Cache. Thus Cache improves the overall performance of the CPU but these numbers shouldn't be considered while purchasing any system. Look at the benchmarks of the CPU as a whole. A CPU with similar architecture but with more cache wouldn't make any noticeable difference. The technology these days have advanced to such a point that the specs of a CPU are just meaningless.

Bassam Ali Mohammed Al-mamari
من قبل Bassam Ali Mohammed Al-mamari , مساعد الرصد والتقييم , برودحي سيستمز

A CPU cache is a smaller faster memory used by the central processing unit (CPU) of a computer to reduce the average time to access memory. L1 (Level 1), L2, L3 cache are some specialized memory which work hand in hand to improve computer performance. When a request is made to the system, CPU has some set of instructions to execute, which it fetches from the RAM. Thus to cut down delay, CPU maintains a cache with some data which it anticipates it will be needed. (L1) Level 1 Cache(2KB - 64KB) - Instructions are first searched in this cache.

L1 cache very small in comparison to others, thus making it faster than the rest.

(L2) Level 2 Cache(256KB - 512KB) - If the instructions are not present in the L1 cache then it looks in the L2 cache, which is a slightly larger pool of cache, thus accompanied by some latency.

(L3) Level 3 Cache (1MB -8MB) - With each cache miss, it proceeds to the next level cache. This is the largest among the all the cache, even though it is slower, its still faster than the RAM. Now you know what cache is and what different level of cache are. And that 6MB value of the L3 Cache in your Intel 4700MQ microprocessor is actually the memory size of that Cache. Thus Cache improves the overall performance of the CPU but these numbers shouldn't be considered while purchasing any system. Look at the benchmarks of the CPU as a whole. A CPU with similar architecture but with more cache wouldn't make any noticeable difference. 

Home Front
من قبل Home Front , فني تكنولوجيا المعلومات , multimedia Center Systems

Cache: SRAM- Static RAM is a memory chip that is used as cache to store the most frequently used data. SRAM provides the processor with faster access to the data than retrieving it from the slower DRAM, or main memory.

L1 Cache: Is Internal cache and is integrated into the CPU.

L2 Cache: Is external cache and was originally mounted on the motherboard near the CPU. L2 cache is now integrated into the CPU.

 

L3 Cache: Is used on some high-end workstations and server CPUs.

Cristian Florin Dascalu
من قبل Cristian Florin Dascalu , IMG Executive (IT / Software) , Wipro Technologies

All three are types of caches used by a computer's CPU. They all exist to speed up the performance of the CPU by anticipating what data it needs. When that data is stored in an L1 cache, L2 cache or L3 cache, the CPU can access and process it much quicker than it can if it pulls it from standard RAM.

The CPU looks for the data in order, which means it goes to the L1 cache first. This is where the data that the CPU is highly likely to need is stored. It is very quick, and it is located very close to the CPU. As a result it is also small, so the amount of data that it can hold is limited.

If the CPU does not find the information that it needs in L1 cache, it checks the L2 cache. This is larger than L1 cache so it is slower, but its increased size means it is able to hold more data.

Finally, if the CPU cannot find what it is looking for in L2 cache, it moves to L3 cache, which is even larger .

Often these caches feed up the chain, so if a piece of data is needed regularly it will move out of L3 cache and up to L2 cache, or out of L2 cache and up to L1 cache.

muhammad saed kayali
من قبل muhammad saed kayali , Senior Engineer , Manpower

L1 smallest & fastest

L3 biggest & slowest

L2 midium

Adam Ahmed
من قبل Adam Ahmed , IT & Web Developer , Freelance

Basm allah alrahman alrahim

 

cache memory is the closeset memory to processor , when the memory is so close that mean faster input output

Usually The cache memory place inside CPU

 

There is also L4 see wikipedia link to know what are the features and benefits of cache

mohamed abd alrahem
من قبل mohamed abd alrahem , حاسب الى , عمل حر

The difference between them very briefly acceleration performance and lower power consumption

Husam Khalifa
من قبل Husam Khalifa , معيد في كلية العلوم - قسم الحاسوب , Baniwalid University

"L1" Level 1 Cache(2KB - 64KB) - is small in comparison to others, making it faster than the rest."L2" Level 2 Cache(256KB - 512KB) -   is a slightly larger, therefore accompanied by some latency."L3" Level 3 Cache (1MB -8MB) -  is the largest among all the cache levels, even though it is slower, it is still faster than the RAM.

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