Overclocking Core i7 920: CPU and DDR3 Memory Speeds & Multiplers

[chriscooke]

Hi there

I'm looking at getting a Core i7 920 with 6gb of PC3-12800 (1600mhz) DDR3 Memory and an Asus P6T Motherboard

I was thinking about overclocking the CPU to around 3.4-3.6ghz, as most people seem to say the i7 will run fairly stable at this speed and the PC will most likely be running 24/7

I was wondering what the options are as regards to getting the memory to run at 1600mhz... as I've heard the P6T only allows for a memory multipliier of 6 or 8 - meaning you would have to run the BCLK at 200mhz to achieve 1600mhz (200 x 8), which would make the CPU run at 4ghz! (200 x 20)

This is how I understand the multiplers for the memory & CPU to work with the BCLK as an example... please someone correct me if I am wrong here

Has anyone got examples of what speeds, multipliers & voltages you've got your i7's and memory runnning at and what memory & board you've gone for?

Thanks

 

[chriscooke]

You only get the even multipliers as far as I know. 6, 8, 10 etc. I've seen a few P6T reporting x20 multi limits, they seem to prefer x19 for maximum clocks.

Does anyone know what the options are for the multiplier on an Asus P6T?

If the memory multiplier was 19 or 20 wouldn't you have to run the BCLK at around only 80mhz to acheive a memory speed of 1600mhz?? Which would cause your i7 920 to run at very slow speeds...! Or am I understanding this wrong?

 

[chriscooke]

So if I want to run my CPU at 3.6ghz, I can run it like this: -

BCLK @ 180mhz x 20 = 3.6ghz CPU / 180mhz x 8 = 1440mhz Memory

but this way the memory would only run at 1440mhz - So if I wanted to run my memory at 1600mhz, could I lower the multipler on my CPU to 18 times with a the BCLK at 200mhz like this?

BCLK @ 200mhz x 18 = 3.6ghz CPU / 200mhz x 8 = 1600mhz Memory

With the BCLK running at a higher speed of 200mhz constantly, is this likely to generate more heat from the motherboard and potentially reduce it's overall lifespan?