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General discussion

DDR3 RAM sold as 1333MHz, but it only runs at 667

Jul 3, 2010 5:07PM PDT

So, I bought a new PC, and the RAM with it was (DDR3,1333MHZ,2 DIMM).
Now, running Garbiel Topala's System Information for Windows program, I see that the RAMs are from Samsung (M471B5273CH0-CH9) Serial D4891B84.
DDR3 (PC3-10700) with a Speed of 667 MHz (DDR3 1333).
What is their speed now? 667MHz? Like RAM from 5 years ago?
It says it can run anything from 5-5-5-14-19 at 381MHz to 9-9-9-25-34 at 685.7MHz.
But don't these chips ever run at 1333MHz?

Thanks for the help.

Discussion is locked

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i/o bus speed?
Jul 3, 2010 5:15PM PDT

according to
http://en.wikipedia.org/wiki/DDR3_SDRAM

the 1333 is the I/O bus speed, in MT/s (whatever that is), and the frequency is, in fact, 667Mhz - but the manufacturer sells it as 1333MHz RAM - are they trying to dupe us (or don't they know themselves what the 1333 stands for)?

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Time to ask more questions.
Jul 3, 2010 8:47PM PDT

One of the advances was to use both edges of a clock to double the speed without doubling the clock rate. This might lead to confusion like this.

If you feel you were shortchanged, go right ahead and complain but to me it seems all that is missing is a short tutorial about how we got here.
Bob