Overclocking - CPU/Memory clarification

[ATLANT3AN]

Hello guys,

I would like to clarify my understanding of this topic, I am waiting for the Q9450 and the Asus Rampage x48 DDR2, I have brought Thermalright Ultra 120 Extreme cooler with a 120mm fan to snap to the side of it.

As its 1333fsb that means divided by 4 is 333fsb which is what we overclock since the Multipliers are locked nowadays as the CPU companies do not wish us to be able to buy a cheaper CPU and make it run faster. The memory is divded by 2 so it will be DDR2 667MHZ by default.

As I am buying 1066mhz capable Corsair Dominator 4GB 2x2gb ram, If I overclock the FSB of the motherboard to 450 which I believe should be easy, 450 x 8 = 3.6ghz and 450 x 2 = DDR2 900mhz.

Is this all correct? and another thing I don't really understand the ratio 1:1 such and such and what is the best way to organize my ram?

Thanks
ATLANT3AN

 

[steve258]

That's right. But assuming the memory is running 1:1 ratio with the FSB. The common options are 1:2, 2:3, and 4:5 on a typical Intel chipset. So:

When @ 1333FSb 333x8=2666Mhz -

FSB:RAM=1:1 RAM Speed: DDR2 667
FSB:RAM=4:5 RAM Speed: DDR2 833
FSB:RAM=2:3 RAM Speed: DDR2 1000
FSB:RAM=1:2 RAM Speed: DDR2 1333

 

[ATLANT3AN]

I don't understand the 1:1 ratio and what the ratios mean or how I space the ram out in the four slots for best performance, DDR2 900 would be classed as what? and could you expand on what this means?

Thanks
ATLANT3AN

 

[steve258]

The ratios are simply ways of setting the memory speed and in the BIOS you probably won't see the actual ratio options, instead you'll see actual speed like PC5300/PC6400/PC7200 but it's the same thing. You should always position both sticks in the same colour sockets for dual channel operation. When the fsb is overclocked to 450Mhz DDR2 900 would be running 1:1 with the fsb as you've suggested in the OP.

DDR2 900 PC7200 has the actual speed of 450Mhz but it's DDR2 900 because of double data rate. PC7200 represents the total theritical bandwidth available at the speed so PC7200 means there's 7.2Gb/s available. As to how the total bandwidth is calculated:

Note: DDR2-xxx (or DDR-xxx) denotes data transfer rate, and describes raw DDR chips, whereas PC2-xxxx (or PC-xxxx) denotes theoretical bandwidth (though it is often rounded up or down), and is used to describe assembled DIMMs. Bandwidth is calculated by taking transfers per second and multiplying by eight. This is because DDR2 memory modules transfer data on a bus that is 64 data bits wide, and since a byte comprises 8 bits, this equates to 8 bytes of data per transfer.