Questions about memory characteristics.

Discussion in 'Computing and Networks' started by Josh Samman, Apr 24, 2013.

  1. Josh Samman

    Thread Starter New Member

    Mar 29, 2013
    11
    0
    Look at this CPU-Z print screen:

    [​IMG]

    Reading some about this subject i found here: http://www.hardwaresecrets.com/article/Understanding-RAM-Timings/26/1 that the maximum theorical transfer rate of my memory module can be "measured" by multiplying its clock by the [number of bits it tranfers at a time (64 in DIMM which is this case) divided by 8] simplifying:

    Maximum theorical transfer rate = clock * 8

    Now looking at CPU-Z info:

    Maximum theorical transfer rate = 533 * 8 => 4.264 MB/s

    My memory is a DDR2-533, PC2-4300 module according to the formula...In CPU-z you can clearly see that size says 1.408 MBytes.

    Now my question is: If the size of the memory is 1.408 MBs why it tranfers 4.264 MBs per second? How that can happen? And how does the CPU fill 1.408 MB fully if the number it's not a power of 2?
     
  2. WBahn

    Moderator

    Mar 31, 2012
    17,758
    4,800
    Your print screen image isn't displaying, so I have no idea what it says.

    Your question is a non sequitur, what does the size of the memory have to do with the transfer rate? It's like asking, if my fuel tank hold 10 gallons, how can I possibly get a flow rate of 100 gallons/minute out of it? Simple, use a big enough pump and accept that your tank is going to be emptied in six seconds.

    I have no idea what the 1.408MB is refering to nor how it is represented. Is it 1.408*1,000,000 bytes or 1.408*1024*1024 bytes or 1.408*1000&1024 bytes ? All three are used.
     
  3. Brownout

    Well-Known Member

    Jan 10, 2012
    2,375
    998
    The data rate isn't dependent on the memory size. at 4.264 MB/s, the whole memory array is accessed in 1.408/4.265s or .330s (330mS).

    CPU's normally access bytes of memory. It needs not be a power of 2. Why do you think it sould?
     
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