EggXpert

ok this is probably gonna be a groaner of a question but I cant for the life of me figure it out...

 how do you OC the CPU with out not being able to OC the memory on a asus p5n-d?

I successfully tightened my memory timings, but as soon as I play with the CPU, it brings my memory speeds down from 900 to like... 720

Ive watched tutorials on other boards and theres usually some sort of cpu speed, and taken that times the multiplier, gets you the ghz of the cpu. As far as I can tell I dont have anything like that on the p5n-d, and the multiplier is capped at 8x.

Using the bios, I got my memory up to 900mhz but couldnt figure out how to OC the CPU. Using Asus' OC tool from Windows, I managed to OC the CPU up to 2.92GHz but that brings my memory speed down, and I cant put my CPU speed up any higher using the windows utility than 365 or the system locks up.  CPU is intel core 2, 2.66ghz E6750. Ive read many reports that this cpu can be pushed easily to 3.2 and beyond so Im obviously failing to see a few things here,

 
A little insight would be appreciated :)
 

Um, by default your memory speed and CPU FSB are linked together, meaning if you increase one it increases the other.

You can modify the ratio at which they are linked by ... modifying the ratio ^_^. Depending on the Bios you have it may be a represted as the FSB:MEM speed or may be represeted as the QAUDPUMPED FSB: DOUBLED MEM Speed. 

333:333 is a 1:1 ratio running your ram at 900 DDR is running it at roughly a 3:4 ratio CPU at 333 and ram at 450ish

It is advisable to use a 1:1 ratio between CPU FSB and memory speed for system stability. At stock speeds a 1:1 ratio for your CPU that means that the FSB will be at 1333(333*4)  and the DRAM will be at 666(333*2).

Running the CPU at 3.2Ghz yields FSB of 1600(400*4) and ram speeds of 800(400*2).

it should be noted that using a ratio other than 1:1 reduces system stability and gives little benefit if you run memory speeds higher.

SOme bios's allow you to change the CPU FSB and Memory speeds independently ( Unlinked) however what its really doing is modifying the ratio and giving you the closest ratio it can find that matches your request for FSB and Memory. What your doing is probably forcing the Ratio to 1:1 and causing your DRAM Freqency to drop.

Hope this helps
 

Ok, well that makes sense. So 1:1 is fine with me I guess.

 So if I understand, raising the CPU is raising the FSB as well? I thought I had read somewhere the p5n-D was notorious for not being able to raise FSB up much past 1333.... but if people are getting 3.2+ that would put the FSB up a lot higher as well, correct?

 Similarly, raising the FSB will raise the CPU speed? so raising the FSB to like... 1600 would run the CPU at 3.2?

 
Still seems like im still missing something here... how can others have such a easy time raising the cpu to 3.2+ if the board cant stay stable beyond like 1400 FSB?
 

ok I am seriously missing something here...

There is another thread active right now that gives insight into how to OC, and like all the others Ive read, it makes mention of the FSB and memory (1:1 333/333 etc) and how 400x8:400x2 should be 3.2ghz cpu and 800mhz ram. This makes sense to me.

 However... 

My mobo does not allow me to change the speed of the straight up FSB speed. It gives me this:

FSB (qdr) 1460
DRAM  1460

I can change the values of those (either linked in a ratio of 5:4, 3:2, 1:1 or unlinked)

So as far as I can tell, the FSB there is being multiplied by 4 before I'm allowed to change it (365x4=1460) and the ram is already multiplied by 2. Is this normal or really strange? Ive never seen it like this in any tutorial or explanation.

 As far as overclocking from windows with a console, I can change the base FSB from 333 up to 365. I have the option to go higher, but putting it at 366 or higher instantly freezes the system, and I dont understand why this is happening either. Voltage is set at 1.6, fyi.

I mean... I would just think my system isnt OC'able except Ive read reports of other people doing it with the same mobo and same chip I have so... i guess im just failing to grasp some concept.
 

im kinda writing this to myself I guess lol... but if anyone wants to jump in and clarify or add their 2cents, feel free. Otherwise, enjoy the magic of learning.

Ok so... i managed to get it up to 3.1ghz in the bios. I set the ratio to 3:2 so I have 1550fsb and ~776dram and that manages to get my comp booted up at 3.1. When I try putting fsb at 1600 (giving me 3200cpu/800memory) the comp wont boot. at 1593 the comp will boot but is not stable enough to make it through 3dmark06. 1594/1595 will boot sometimes but usually freezes after a few minutes. Im still not understanding how people are pushing this cpu to 3.2/3.4/3.6 and beyond. i have tried playing with the voltage, the highest I read reports of was 1.52 so I tried everything between 1.40v and 1.52v @1600fsb (3.2ghz) but nothing worked, it always froze trying to load windows. If anyone has a asus p5n-d with a E6750 (or even just a p5n-d mobo) I would love to get an idea of how you go about OC'n the cpu. Frankly I'm stumped as to how to go about getting higher speed out of my cpu.

 on a side note, i did get my gfx card core clock at 795mhz, any higher wont make it through 3dmark06. palit 8800gts 1gb. playing with the memory clock or shader clock did weird stuff that was a pain to reverse, so im not gonna monkey with that. Does this sound about right? just curious.

1) Running more than two sticks of ram decreases system stability

2) Running in anything other than 1:1 decreases system stability. Try increasing your ram Voltage and OCing your ram along with CPU, you may get better stability like that.

3) Try increasing the Northbridge/southbridge voltage.

5) make sure you have turned off all spread spectrum features. 

1) by how much? a ton? or just a little. I have 8gigs which I know is waaaaaay unnecessary lol but, wth right? My room mate is lookin to build a comp here soon though, so if its a huge deal I can sell 2 sticks to him. Otherwise, I'm just looking to max out what I have, not necessarily break records hehe. I did think something was up, though, that no one else waws using more than like 2gigs for OC rigs.

2) ok so if i did a 1:1 lets say... 400. Everything I've been reading about my ram is that it shouldnt need to be voltage'd much higher than 2.1... which is what mine is at. How much higher before I burn it? I mean, I guess I can try it.

3)havent tried that yet, never noticed any mention of these values, i will look them up and try it out.

5lol) not sure what this is... are these the random power saving features in the bios? I have most things disabled, I did manage to either discern them as unnecessary from the bios description or found explanations in the 'net and that it was ok to turn off for oc purposes.

----edit

I'd just like to add this thought. My ram is set at 900 right now, and fsb is at 1580 (8:9 ratio) and the system runs stable. Thats ram444 and cpu395. Supposedly, 1:1 is more stable than what I've got going right now, so if I put my ram down to 400, and bumped the cpu up to 400 (ie setting my ram to 800 and fsb to 1600 in my bios) that should work right? But it doesnt. Doesnt really seem to matter that I do with the ram... but if try to push my cpu up past 395 it gets very angry and goes right past unstable into wont-even-boot. Is this normal?

Well I did some more research and found some values that I though I'd try....

 438:438 vcore 1.425v... so 3.5ghz. Thought... what the hell, ill try it, so i put it in and bam, booted up at 3.5

Ran 3dmark06 and got 13177. No clue if this is good or not, but top 'similarly configured system' was 17000+ so I have no damn clue hot to achieve those numbers.

So I guess Im getting closer to understanding this stuff... *shrug*