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I have a doubt whether cache memory is located in the processor or at the motherboard?

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Sounds like school assignment. – Olli Feb 28 '11 at 11:00
    
Sounds like plain lazy – Shekhar Feb 28 '11 at 11:28
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@Olli @Shark Sounds like you guys are whiners... – BloodPhilia Feb 28 '11 at 11:39
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And for the record, there has been a time the cache memory was located on the motherboard, so I understand there can be some confusion. (Check this page from 2001: pcguide.com/ref/mbsys/cache/structMotherboard-c.html) – BloodPhilia Feb 28 '11 at 11:40
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This question is redundant. All CPUs have some amount of cache, and motherboards themselves usually do as well (although it is not a requirement, it depends on the specific architecture). This is like asking "do cars run on gas or diesel?". Voting to close. – Breakthrough Feb 28 '11 at 12:16

Most computers have a multi-layer cache approach. The first layer - L1 cache is always located on the processor. L2 cache, the next layer up, can either be located on the CPU or on the motherboard depending on the architecture. Some systems also have a third layer of cache L3 which again could be located on either the CPU or the motherboard.

Older 486 systems, for example, had L1 in the CPU and an optional L2 on the motherboard.

Most modern systems have all the cache on the CPU.

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+1 Good answer! – BloodPhilia Feb 28 '11 at 11:42
    
Around that time all cache on the motherboard was also common. E.g. the en.wikipedia.org/wiki/DEC_Multia I owned shipped with no cache and an option to add L1 cache on the motherboard. – Hennes Dec 17 '15 at 14:02

Kind of obvious, but anyway.

From Wikipedia:

A CPU cache is a cache used by the central processing unit of a computer to reduce the average time to access memory. The cache is a smaller, faster memory which stores copies of the data from the most frequently used main memory locations.

Thus, the cache is always attached to the CPU itself and has nothing to do with the motherboard or even the memory.

Edit: Some people feel the need to downvote without giving comments, so I might want to add that this holds for modern systems as cache could be used on motherboards too, but isn't nowadays.

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All that quote (and really the first line of the wiki article) states is that the cache is used by the CPU, no mention of where it is stored. You can store L1 cache on the motherboard with a high throughput bus to it and it would still be "cache used by the central processing unit" – Matthew Dec 17 '15 at 14:07
    
@MatthewVerstraete Please read my post again in which I explicitly said that cache could be used on motherboards, too. – slhck Dec 17 '15 at 15:20
    
I see where you state " the cache is always attached to the CPU itself and has nothing to do with the motherboard or even the memory." but that does not clearly define where the cache is at. An attached HDD does not physically sit on a MB or anywhere else yet it is attached. – Matthew Dec 17 '15 at 15:30

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