CPU Speed and No. of Cores

Hello,

I have a server with " 4 cpu's(cores) , each 4.7 GHz"
another server with " 8 cpu's(cores) , each 2.8 GHz"
so will there be a difference in the performance ?
7 answers Last reply
More about speed cores
  1. Hi and welcome to Tom's forum.

    Sure it is, more cores are always better than core speed. Just to know, how do you get those 4 cores to 4.7GHz?
  2. chetanshinde said:
    Hello,

    I have a server with " 4 cpu's(cores) , each 4.7 GHz"
    another server with " 8 cpu's(cores) , each 2.8 GHz"
    so will there be a difference in the performance ?


    It depends.

    If your workload can keep 8 cores fully busy, then 8 cores may be better.
    If not, then 4 faster cores may be better and response time will be better.

    The key is utilization, regardless of 4/8 cores. Once you start to go over say 75% utilization, queue lengths will build and responsiveness will suffer.
  3. geofelt said:
    It depends.

    If your workload can keep 8 cores fully busy, then 8 cores may be better.
    If not, then 4 faster cores may be better and response time will be better.

    The key is utilization, regardless of 4/8 cores. Once you start to go over say 75% utilization, queue lengths will build and responsiveness will suffer.


    Agreed. More cores doesn't mean faster performance, the question comes into how many threads are being saturated / utilized and the type of data being processed. If your application(s) can utilize more than 4 threads of data, then the 8 core system should perform better.

    On the flip side, if your application(s) only use 1-4 threads, then the faster clock speed of the 4 core system will be more beneficial.
  4. It also depends on what the CPUs are, if the 8 core server is an older dual Core 2 Quad system and the 4 core server is using a Nehalem or Sandy Bridge based chip it would perform better in many cases, especially if it has hyper threading to go with its 4 cores.
  5. As a simplistic exercise, 4.7 x 4 cores = 18.8
    2.8 x 6 = 16.8
    2.8 x 7 = 19.6

    It will take an average utilization of 7 cores to beat the throughput of the faster 4.7 4 core system.
  6. geofelt said:
    As a simplistic exercise, 4.7 x 4 cores = 18.8
    2.8 x 6 = 16.8
    2.8 x 7 = 19.6

    It will take an average utilization of 7 cores to beat the throughput of the faster 4.7 4 core system.


    This is assuming the application will utilize all core simultaneously. if only 4 or less cores are being utilizes at one time then the 4.7 x 4 will outperform the 2.8 x 8
  7. 3xch4ng3 said:
    This is assuming the application will utilize all core simultaneously. if only 4 or less cores are being utilizes at one time then the 4.7 x 4 will outperform the 2.8 x 8

    True enough, my point was, that even at a utilization of 6@2.8 , the faster 4 core would be better.
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