title: Why writing speed of RAM is coming far less than what is mentioned on it?
body: <p>I uses below command to measure the ram writing speed but it is showing me far less than what is mentioned on RAM.</p>
  
  <pre><code>time dd if=/dev/zero of=tes bs=100M count=10 oflag=dsync &amp;&amp; sync
  10+0 records in
  10+0 records out
  1048576000 bytes (1.0 GB) copied, 1.05167 s, 997 MB/s
  
  real    0m1.056s
  user    0m0.001s
  sys     0m1.053s
  </code></pre>
  
  <p>I am using DDR3 and calculating theoretical max ram speed by below formula is:</p>
  
  <pre><code>Max transfer rate= clock x no of bits / 8
  DIMM module transfer 64 bits 
  Max Theoretical Transfer Rate= clock x (64/8)
  =1333 x 8  
  =10,664 MB/s
  </code></pre>
  
  <p>So theoretical expected speed should be 10 GB/s (approx) but in reality it is comming out far less. So Can anyone please tell me why?
  Thanks in advance!</p>