Asrock z77 extreme 4 detecting my RAM in lesser speed

karthikparys

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Sep 2, 2012
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I have couple of confusions and troubles in my setup with the new system.

The second one here am putting is,

The board is detecting my corsair vengance DDR3 1600 mhz RAM as 1333 mhz.

Why is it ?

if i change it in OC tweaks of the bios menu, is it like OC or just adjusting to what it should be.


Help pls.
 

Your motherboard's EFI BIOS is not set to use XMP Profiles by default.

You can change the EFI BIOS setting to use the XMP Profile(s) instead of the default JEDEC SPD Timings Table entries. It will then be using the XMP-1600 timings instead of the JEDEC 1333 MHz timings.
 

DDR = Double Data Rate

800 MHz external memory clock frequency x 2 = 1600 MHz

Everything is working correctly.

You were running at 666 MHz external memory clock frequency initially which resulted in the 666 x 2 = ~1333 MHz memory clock that you said that you were running at when the memory modules were first installed.
 

karthikparys

Honorable
Sep 2, 2012
23
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10,520



Really, So it always show half of the speed in the display !!! Never heard of like this.
 
Yeah that's what it is, the RAM's clock (I/O bus clock) is 800MHz but the effective clock relative to the FSB/BCLK is double (Data rate).

If you know what a 'Sine Wave' is then the memory pulse (strobe) is on both the top & bottom, so data is transmitted twice per clock cycle.

This idea isn't much different than a CPU Clock, but the multiplier is much higher.