5 Replies Latest reply on May 28, 2015 11:05 AM by rguevara

    Frequencies of the L1, L2, L3 caches.

    Sergey_85

      Need answer from employee of  company Intel.

      10-20 years ago caches of processor has that features:

      - cache L1 integrated in processor, have smallest size and speedest frequency;

      - cache L2 integrated in motherboard, have frequency = frequency of data bus. Biggest than L1, but many slowly.

      What features have caches of processors now (i3 and newer)? I have 3 answers, need faithfull:

      1. L1 < L2. L2 < L3. L1 speedest L2, L2 speedest L3.

      2. L1 < L2. Frequency L1 = frequency L2 = frequency of processor's core. Frequency L3 < L1.

      3. L1 < L2. Frequency L1 = frequency L2 = frequency of processor's core. Frequency L3 = L1.

        • 1. Re: Frequencies of the L1, L2, L3 caches.
          allan_intel

          I am currently researching on this issue. As soon as I can, I will send you a message with my findings. Thank you for your patience and understanding.

           

          Allan.

          • 2. Re: Frequencies of the L1, L2, L3 caches.
            Sergey_85

            Addition: maybe influences for speed caches that value: CAS-latency as decelerating, analogy RAM.

             

            For example: frequency L1 = L2. But latency L1 < latency L2. Conclusion: L1 fastest L2.

            • 3. Re: Frequencies of the L1, L2, L3 caches.
              Sergey_85

              I got that:

              - Intel. Intel® 64 and IA-32 Architectures Optimization Reference Manual: p,2-18, chapter 2.2.5.1, table 2-11.

               

              Frequency L1 = L2 = L3. But latency L1 < latency L2 < latency L3.

               

              L1 fastest (latency 4), L2 slowly (latency 12), L3 lowest (latency 26-31).

              • 4. Re: Frequencies of the L1, L2, L3 caches.
                rguevara

                Hi Sergey_85,

                 

                Intel(R) Core(TM) i7 / Intel(R) Core(TM) i5 / Cache Hierarchy:

                The first level cache consists of a 32K L1 data cache and a 32K L1 instruction cache with one cache allocated per core. The second level cache is a high speed 256K cache for data and instructions with one cache allocated per core. The third level cache is a 8Mb inclusive cache logically shared across cores for Intel(R) Core(TM) i7 5xxx processors and a 6Mb inclusive cache shared across cores for the Intel(R) Core(TM) i5 5xxx processors.

                 

                I hope this helps,

                • 5. Re: Frequencies of the L1, L2, L3 caches.
                  rguevara

                  In addition to that: Intel(R) Core(TM) i3  Cache Hierarchy:

                  The first level cache consists of a 32K L1 data cache and a 32K L1 instruction cache with one cache allocated per core. The second level cache is a high speed 256K cache for data and instructions with one cache allocated per core. The third level cache is a 3Mb (Core i3 41xx/T) and 4Mb (Core i3 43xx/T) inclusive cache logically shared across cores.

                   

                  I missed that part on my original answer.

                  Regards,