# 1333Mhz DDR3 shows as 667MHz



## huntdawn (Aug 3, 2013)

Hi guys,

I have an alienware Mx17 R2 that I upgraded with 16GB of RAM (1333MHz DDR3) a few months ago, from Crucial.
However, I just checked using CPU-Z and speccy and they both show that the RAM speed is 667 MHZ which is very strange.
I could supply also a foto of the RAM chips if needed, but I just checked and they definitely indicate that the supported speed is 1333MHz.
Something is going wrong or am I missing something?


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## erocker (Aug 3, 2013)

667 x 2 = 1333. That's the way it's supposed to be. DDR stands for dual data rate.


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## CounterZeus (Aug 3, 2013)

DDR = double data rate, meaning it can send double info even though the base clock is 667. So 667*2 = +-1333MHz. Nothing is wrong


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## cdawall (Aug 3, 2013)

Yup that's perfectly 100% normal.


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## huntdawn (Aug 3, 2013)

Thanks guys, I really appreciate it. :O)


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## McSteel (Aug 3, 2013)

That's actually perfectly wrong, but everyone just got used to the error.

Your memory has a _transfer rate_ of 1333 _MT/s_ (MegaTransfers per second). Double Data Rate means that the memory does a data transfer both at the leading and the trailing edge of a signal. If it's work frequency is 667 MHz (667 millions of signals per second), then it will do 1333 millions of transfers per second (two per signal).


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