OC an e6600 on an EVGA 122-CK-NF68-A1 680i SLI.

[shujinko]

Hi, this is my first post here.

I just built a system with the above motherboard and processor, as well as 2GB (2 x 1GB) of Mushkin HP2-6400 memory.

Currently, I'm overclocked to a 1275FSB, with a 3:2 memory clock divider. This results in a 2.868Ghz processor clock (318.75 x 9) and a memory clock of 850Mhz at 2.150 volts. I ran Prime 95's torture test for 8 hours with 0 warning and 0 errors with these settings.

I have a case that moves a lot of air, and a Thermaltake copper sync/fan. My processor temps under load have not gone higher than 52 C.

I was wondering what everyone's opinions were about heading to 3.0Ghz. I tend to be a more conservative overclocker, and with the 3:2 divider being the most conservative my board offers, I'm worried about pushing it too far. It seems that to hit 3.0Ghz, I'd have to do 1350FSB, which would result in the memory running at 900Mhz. The modules are rated for up to 2.2v, but I'm told DDR2 gets volatile after 2.1v.

Should I stay at 2.87, or will 3.0Ghz be fairly safe? Or, If I'm misunderstanding the memory frequency as a result of the divider, please let me know. This is my first build with a clock divider like this.

Thanks all.

 

[raven_87]

go as far as possible without pushing the voltage to your ram.

if you have active cooling, 2.2v is doable - but dont overstep your boundaries. usually your gut on how far equipment will go is correct.

other than that it sounds fine. whats your northbirdge voltage at?

 

[aoe]

Posted a response to your question in this thread.

Basically, I think you're misunderstanding how the memory frequency is calculated.

At an OC of 2.87GHz, FSB = 319MHz (E6600 has a 9x multiplier). At a 3:2 ratio (FSB:RAM), the resulting memory frequency is calculated as:

FSB / 3 * 2 (ratio) * 2 (DDR - double data rate)
319 / 3 * 2 * 2 = 425MHz

You can check this using CPU-Z.

I would suggest you set your ratio to 1:1 and continue OCing (if you want to go further). 3GHz should be easily achievable on air.

 

[shujinko]

Yes, that's correct. These numbers I'm reporting must be the result of "rated" speed.

For example, CPU-Z says my bus is 319 (1275 rated) and that the memory is running at 425 MHz. In my BIOS, I'm asked to enter my bus speed (which I put in as 1275 manually) and with the 3:2 divider, it spits out a memory speed of 850 Mhz, which must be 425 (rated twice as high because of dual channel maybe)? Because right now when I boot, it says "Memory clock is 850Mhz", so it must be doubling it because of dual channel, no?

Here's a screenshot of my BIOS.

If I set the clock mode to "Unlinked" it will let me change these values independently.

 

[IcY18]

no it doubles because its DDR, Double Data Rate memory. You want your memory to run at a 1:1 ratio with your cpu. It will result in a higher stable overclock. Leave the memory and cpu at 1:1 and go for 3.0ghz, you should easily be able to achieve this as long as your cpu temperatures don't go too far over 60C.