Question about FSB and Memory

vivi_ornitier

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Feb 7, 2008
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Hey, got a quick question, kind of confused about this.

On the overclocking guides, specifically with DDR2, I see FSB values of 400-500mhz and if you want a 1:1 ratio with the FSB and memory, say for example 400mhz, you should use DDR2-800 since DDR2 memory operates at double the FSB speed. The 400mhz is then quad pumped to an effective bus of 1600.

Now i am reading that DDR3-1600 is a FSB value of 400mhz at 1:1 since DDR3 memory works at 4 times the FSB speed (one of their perks).

Another example would be overclocking a DDR2 system to 500mhz (QDR2000) would require DDR2-1000 and would be the same as DDR3-2000.

So my question is: Do both DDR2-800 overclocked to 400mhz (which is 1:1?) and DDR3-1600 work at the same FSB frequency and are basically the same thing in terms of performance?

Thanks for any help with this matter.



 

vivi_ornitier

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Feb 7, 2008
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yes, I read the wiki on DDR3 and it doesn't quite flow with the article on DDR2.

Mainly due to the I/O Bus speed of DDR3 is 667 and memory clock of 133 @ DDR3-1333 which in turn would give (133x9 = 1.2 Ghz on a E8400) which is wrong cause the memory clock suppose to give (333x9 = 3Ghz) which is correct for the DDR3 setup. Or is this wrong?

On the DDR2 article, for I/O Bus speed of DD2 is 667 and a memory clock of 333 @ DDR2-1333 which in turn would give (333x9 = 3Ghz on a E8400) which is correct.

So why is the memory clock and I/O Bus so different?