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I have read that there is a speed difference between 1066 and 1600 DDR3 RAM, but is it significant? I'm building a computer for resale, and will having 1066 MHz RAM in it be a negative? I could probably upgrade from 4GB 1066 to 4GB 1600 for a bit, but only if its really worth it.


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That is hard to explain in a short page, but anandtech already done a long exhaustive explanation about RAM and you are better off reading there:… - They are using g.skill brand as an example, but the explanation goes with ANY memory. (First page is the explanation, 2nd page onwards are the comparison of RAMs they tested) – Darius Oct 31 '13 at 0:21
Ill take a look, thanks! – Nathan Oct 31 '13 at 0:32

You need to match the memory to the motherboard and the CPU. If the motherboard only supports 1066 then 1600 will still run at 1066 and the extra speed is wasted.

Likewise, if the CPU does not support the speed the extra speed is also wasted.

If all 3 parts (cpu,motherboard, and ram) support 1600 then you will benefit from the speed.

For normal users the difference will not be that noticeable. However, if you run memory intensive applications the minor difference will add up over time. For example, seti, and other distributed software. Anything that is intensive and runs for a long time, video rendering.

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Of course there is a speed difference between the two, it's in their name: 1066 DDR operates at 1066 MHz, while 1600 DDR operates at 1600 MHz, so it is 50% faster.

These are the maximum speeds at which these two memories can operate: if you insert a 1600 DDR bank in a slot that is clocked at 1066, it will work at the reduced speed, and you will have wasted your money.

Also, just to be complete, in truth these chips work at half the frequency quoted above. However, they transfer two data units per clock cycle: this is the meaning of the first D in DDR: Double Data Rate. In other words, they are twice as fast as SDR memory (which, I bthink but am not sure, is not used in pcs any more). Because of this double efficiency, their quoted cycle is twice the true clock speed at which they work: in other words, 1066, 1600, and so on are the effective data transfer rates achieved.

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