My setup:

Q6600
Abit IP-35 Pro mobo
4 GB (2x2GB) G-Skill DDR 800 RAM


My VID is, as stated in the topic, 1.325. I've got it to 3GHz without any problems, but can't seem to push past that with stable results. I've tried for 3.2 and 3.6 at voltages as high as 1.4925 and though I can boot into XP, when starting up Prime95 the 4th core instantly drops out and the system is prone to blue-screening.

I'm using auto-voltages in the BIOS for my current stable 3GHz OC, but bumping the clock up past it with auto settings still produces unstable results (this includes running it at 3.15Ghz with the ram underclocked, 3.2Ghz with 8x400fsb, and 3.6Ghz with 9x400fsb.)

Temperatures have not been an issue as of yet. I'm using a xigmatek SD-1283 (I think that's the model) cooler, and at 3Ghz my core temps idle at 20-25 degrees and hit no more than 45 degrees under prime 95 load.

My goal is to hit 3.6Ghz, but at this point, I'd just like to be able to push past the wall of 3.0Ghz I seem to be at.

Any suggestions?

Also, when manually playing with voltages, I've increased voltages on the processor only. I didn't feel I was knowledgeable enough to mess around with mobo/ram voltages.

Yes, it is possible. My Q6600 with the same VID hits 3.6Ghz 100% stable with 1.55V. Any less and I will loose a core under Prime95 after 1-3min. Of course not all CPU/Mb's are the same. Your CPU or Mb may not be up to the task of running past 333Mhz on the FSB.

Here is where I would start.
Check to see if a newer BIOS for your Mb supports 1600FSB. If it dose, the auto voltage settings should supply just as much power as the manufacture recommends at that speed. If not, leave it on auto and check the voltage from windows. After your CPU is 100% stable, start taking it down a notch at a time. Re test every adjustment until you find the minimum stable voltage.

Add more voltage. The commonly accepted max voltage for the 65nm Core 2 architecture is around 1.5V. Depending on your cooling, it is possible to add some more but be careful with your temps. I run my Q6600 at 1.55V only when I am playing a demanding game but never seem to have to much of a temp spike compared to my normal speed of 3Ghz.

You can run your RAM at 1:1, stock voltage and timings when you push to 3.6Ghz.

If you are still unable to reach 3.6Ghz, raise your CPU and Nb voltage, drop your RAM to 1:1 and start raising your FSB 5-10Mhz at a time. Give a quick 10min Prime95 test every bump. If it passes, raise it 5-10Mhz more until you find your hardware's wall.

Best luck.
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Without looking it up, i'm going to assume your mobo natively supports a rated FSB of 1333mhz. So by increasing your FSB past that you've gone into the realm of unknown. Where things are chaotic, and evil, or just plain wrong.... Oh i mean, you probably just need to bump the voltage up on the Northbridge

is your CPU a g0 stepping? I'm assuming it is based on the temps you listed but if its a B3 im not sure you will make 3.6 at all. I agree with the above poster about updating the bios, a lot of those p35 motherboards have come out with new bios revs that officially support high fsb settings. One thing you could try, lower the multiplier of your chip to 8, 7, 6, or whatever, and then raise up the fsb of the motherboard to get the stock clock speed of your chip. That way you can find the max fsb of your motherboard, so you know what your limiting factor is. Right now you are working with two unknowns which is tough, how high fsb does the motherboard support, how high can the chip go. Typically i have gotten G0 Q6600s to 3.6Ghz 100% stable with 9X400 1.425 - 1.45 vcore. Good luck in you quest!

Don't assume that your VID has anything to do with overclocking.

VID is a lot more complicated than everyone thinks, and has absolutely nothing to do with how a cpu will oc as far as anyone has been able to conclusively show. You can get different VID readings on a cpu in different motherboards, depending on what voltage regulation chip it uses. This alone is enough to make VID useless for predicting oc'ability.

The VID is hardcoded into each individual cpu, but it's not just one number; it's a range of 6 different VID levels and these levels are specific to each individual cpu. VID is not static and changes with power requirements. VID can fluctuate almost constantly to try to maintain the level programed into it during manufacturing.

I was just curious what CT actually reports, is it reporting the VID being used at the time, max VID, etc.. VID is read from a sense line off one of the cpu pads, it seems like CT would have to be reading whatever VID level is in use at that time.

Here is an explaination of VID on C2D processors, this is the short version, the whole thing explaining all the levels, how it's read, etc.. is available in the data sheets for the cpu's on Intel's site..

Individual processor VID values may be calibrated during manufacturing such that two devices at the same core speed may have different default VID settings. This is reflected by the VID Range values provided in Table 5.

The processor uses six voltage identification signals, VID[6:1], to support automatic selection of power supply voltages.

The processor provides the ability to operate while transitioning to an adjacent VID and its associated processor core voltage (VCC). This will represent a DC shift in the load line. It should be noted that a low-to-high or high-to-low voltage state change may result in as many VID transitions as necessary to reach the target core voltage.
Transitions above the specified VID are not permitted. Table 5 includes VID step sizes and DC shift ranges. Minimum and maximum voltages must be maintained as shown in Table 6 and Figure 1 as measured across the VCC_SENSE and VSS_SENSE lands.

Lupi's VID didn't change in Coretemps when he tested his 10 Q6600 on 3 different motherboards. After doing some OCing on all of them, he saw that there was negative correlation between VID and OCing potential. Of course he ran into 1 or 2 sample that had low VID but didn't OC well. I suppose from this you can conclude that a low VID chip has a better chance at getting a better OC.

Anyhow, 3.6GHz should be possible for most Q6600s. How much voltage you need is a different issue. With Lupi's ultra low 1.200VID Q6600, he only needs 1.3125v to get Prime95 stable at 3.6Ghz.

lol, lucky lupi. Any ways, has any one ever gotten a .85v VID CPU? The Intel website lists VIDs from .85v-1.5v ( http://processorfinder.intel.com/d [...] Spec=SL9UM ) for the Q6600. Most other CPUs have a minimum of .85v, so I am wondering if any one has a .85v VID CPU?

Quite doubtful. Lowest I've seen was near 1.125V I think.

Also another thing I have noticed is that the website reviews for CPUs NEVER tell you the VID. All they show are the CPUZ screen shots,etc. To me VID is one of the biggest OCing factors, ranking in the same range of heat, CPU architecture, cooling,etc.

@Evilonigiri: Don't you have a job? Most ppl. are at jobs at the current time.

I did not realize that there was so much variation. Mine is 1.2625 volts. Using a TRUE, I can reach 3.0 GHz with stock voltage, 3.3 GHz at 1.300 volts, and 3.6 GHz at 1.45 volts (BIOS setting, droops to 1.400 volts on a GA-EP35-DS3P motherboard, all Prime 95 stable after 24 hours.

eldredpe:
I try to avoid "AUTO" settings whereever I can.

Well, it could very well be something that's accompanying low VID that helps OC, so perhaps it's not the VID that's affecting the OC but the part that's accompanying low VIDs. See, in some cases low VID doesn't translate into good OC.

But then again, what do I know?

You could have issues with not disableing speedstep and other features that help overclock when disabled.

I do believe my mobo (at least from what the box says) has only a 1333 fsb. I'll check for an update.

Also, how much extra voltage is safe to give to the northbridge?

And to the Q6600? It's rated for up to 1.5 I know, if I push a bit past that is it going to fry the chip?

Nope, but it's not exactly a good thing to do. People has run them at 1.6v or even higher, but those chips aren't expected to last more than 2years.

For your NB voltages, increase it by .1v or so. If it's not enough just increase it.

what vcore value should we use. bios or cpuz.