Requesting input on OCing Q6600

S

skullkyng

n00b
Joined
Jan 24, 2008
Messages
49
Hello all, I'm a first-time OC'er so, bear with me. I've read the FAQ's, and it is incredibly helpful. Unfortunately, I still have a few questions.

Here's my set-up:

Abit IP35 Pro mobo
C2Q Q6600 G0 stepping
ZALMAN CNPS9700 LED 110mm 2 Ball CPU Cooler
G.Skill DDR2 800 (F2-6400CL5D-4GBPQ) 8Gig
Vista 64 bit.
Project S-D case (see worklogs, it is a custom server case, should have decent airflow though)

So, how does one go about picking a number to OC to? If I lived in an ideal world, I would like to get up to, or as close to 3.6 GHz as I could.

Thus far, I've gotten it to boot up to 3.2GHz. Past that, It fails POST and restarts with stock settings. Currently, I'm leaving the voltages on Auto which are:

CPU core Voltage - 1.325v
DDR2 Voltage - 1.8v
CPU VTT Voltage - 1.2v
MCH voltage - 1.25v
ICH voltage - 1.05
ICHIO voltage - 1.5

I've been keeping my FSB / RAM in a 1:1 ratio.

I suppose my question is... If I wanted to push my CPU past 3.2, what would be the most likely place to start making adjustments. My coretemp readings are all at 25°c at idle at 3.2GHz, so it still looks like i have a decent window to work with there.

Any help?

Thanks!
 
Download Prime95 and Core Temp and check your temperatures when the cores are all at 100% load. Idle temperature is not what's important.

You can also go to options in Core Temp and set "Show Delta to Tjunction max temp".

Also run Prime95 for at least 1 hour at each clock when you're working your way up to see if it's stable, then when you've found your max clock, what you're comfortable with considering temperatures and voltages run Prime95 for 8 hours or so. You should get no errors. If you do get errors you have to lower your FSB or increase your voltages, or adjust your memory settings. Oh, remember to activate "Round off checking" under Advanced in the menu of Prime95.

You don't just pick a number you want to OC to, you work your way up and see what your CPU, RAM and MB can do.

Just try 3,2 or 3,4, if you can't get into Windows or if you get errors in Prime95, or bluescreens, you up the voltage a notch or to, and try again, then repeat.

At higher clocks, in my experience 3,6 and up to 4GHz on Q6600 you also have to adjust other voltages than your vcore to get your system stable, for instance North Bridge voltage.
 
RealTemp is probably better for measuring temps these days. It's amazing at the differences you can see when using different sensor monitoring apps - but of all of them, RealTemp is now my new fave because it truly seems to provide the real temps as well as a host of other info as well. Great software, highly recommended for temp monitoring.

As for Prime95, a single instance of it is useless as he's got a quad - and yes, you can hit all 4 with it but that's a pain to set 4 different copies of it with processor affinity for individual cores. ORTHOS is what's better for that as it handles at least dual cores, so you run two copies and then it'll cover all of them on the quad. I hadn't run ORTHOS on my Q6600 since I got it on Saturday sooo...



Figured I'd run it for a few mins and see what's up. Two copies, first copy with affinity to CORE0 and CORE1, second with affinity to CORE2 and CORE 3. The Q6600 is a ~3 GHz (9x333), PCI-E bus is set to 100, Vcore is stock 1.325, RAM is set at 2.4x (for 800, since it's DDR2 6400 Corsair XMS2). Looks ok to me, temps are where I expected them since I'm just using the stock Intel HSF. Will upgrade to something better later on, but for now everything is rock solid stable running Window Server 2003.

Good luck...
 
Hey all,

I must have written that above post poorly. I've been running CoreTemp and Prime95 from the beginning. Sorry about that.

At any rate, I'm working on a 3.3Ghz OC on my Q6600, and thus far, it seems to be doing well. (I've been slowly crawling up to stability).

Do any of these voltages seem high, esp my V-Core?

V.Core - 1.4150
VTT - 1.35
MCH - 1.44
ICH - 1.09
DDR2 - 1.9 (top end of stock spec for RAM)

My last two Primetests increased the V.core:

1.3950 - lasted 20 sec before error
1.4050 - lasted 3 min before error
1.4150 - still testing, but has been going strong for several minutes now.

My temps are great: 47-48° on all cores.

I guess I just keep thinking my V..core is high, but it is working...

Any feedback, suggestions? (i'm on my 27th iteration of this OC...)
 
I use water cooling, but the VCore on my Q6600 is 1.43V
I have an "old" 680i board and all it will do is 3.1 GHz no matter what I try.

That said, I get about 55C with Orthos x 4.
Under gaming load, which is way more real world, my CPU rarely sees 40C.

Your stuff looks fine.
 
Looks good so far, keep it up. If using air, try to keep vcore under 1.5 id say but its really dependent on temps. Saying that stay under 65c if you want 24/7 clocks.
 
While your temperatures look good your voltage is high IMO. I have a very similar system and I'm able to hit 3.0 GHz at stock voltage. I'd highly recommend not running your voltage control on auto. I would do this:

Go into BIOS and Load Optimized Defaults, Save and Exit.
Immediately enter BIOS and set your voltage control to manual.
Bump your MCH up a notch or 2 since your running 4 dimms of RAM, and set your DDR2 at the mid-point of its rated voltage (~1.85)
Set your FSB up ~ 30 MHz and check for stability and temperatures as you have been.
Keep your memory ratio at 1:1 for now (as you have been) to ensure it's not the cause of any instability.

Keep bumping your FSB while remaining at stock voltage until you become unstable. At this point you can go in and bump your CPU core voltage up. I think you'll find that you can get a higher overclock with cooler temperatures by going this route.
 
So I got everything pretty stable in 3.3 GHz, and am working at 3.4GHz. When I list the voltage for the CPU on the forum, should I list the amount I enter in the bios, or the amount CPUZ reads when the CPUs are at idle.

For example, for 3.4GHz, I'm currently at:

On the bios, I'm at 1.4450
on CPUZ, I'm at 1.420

I'm fairly stable at 3.3GHz, but I've only tested it for about 1.5 Hrs. I'll come back to it, if I cannot get anything higher or the voltages start to weird me out.

The voltages I have for 3.3 are:

V.Core - 1.4 (CPUZ) - 1.4250 (Bios)
VTT 1.2 (stock setting)
MCH 1.25 (stock setting)
ICH 1.05 (stock setting)
DDR2 1.9 - top of stock value.

Do these look pretty good? Anything seem off?

Thanks!
 
Well, I think I finally have it pretty stable.

My final OC specs are:

3.3GHz (up from 2.4GHz)

V.Core - 1.4350 (in the BIOS), 1.410 (In CPUZ)
VTT - 1.20 (stock setting)
MCH - 1.25 (stock setting)
ICH - 1.05 (stock setting)
DDR2 - 1.9 (top of stock setting).

My temps under full load across all cores range from 49-52°c, depending on ambient temps. I ran Prime95 for 15 hrs+/-

I thought about pushing my OC a little more, but I would feel uncomfortable running any higher on the CPU voltage.

Any thoughts on how to maybe lower the V.Core (like is there a voltage trade-off anywhere, for example, raising the VTT a bunch means I can lower the V.core a little) - or it just is what it is?

One last thing, am I correct that the voltage not to exceed on the Q6600 is 1.5v? Also, how close can you get to that before it gets really hairy, or just chews up the lifespan of your processor?

Thanks!
 
My Q6600 is a B3 stepping with 1.3v VID (coretemp will show the default VID when the CPU is loaded) and running on an Asus P5K Delux (P35 chipset)

For 3.2GHz (8x400) I have

Vcore = 1.45v shown in CPUz (1.495v in BIOS)
VTT = 1.3v (1.2v gave me slight data corruption, showed as Prime crash after 2h and random errors on video encoding. This is mainly because I am using 1600fsb)
MCH = 1.3v (dafault is 1.2v but using 4x 400MHz memory moduals it needed a bump to pass Memtest)
All other settings are default.
Memory voltage is as per the spec of your memory (suggest testing with Memtest if you have any suspision about its stability), possibly 0.1v over spec if you have more than 2 moduals.

For me this is stable for 4h prime but it kicks out alot of heat, the CPU alone is hitting almost 200W output and along with an overclocked 8800GTS it gets warm in my room. I know its pulling alot of power as I used to trip an iGreen 600W PSU at 3.4GHz and 1.52v when all cores loaded and 3D playing. BTW all the above is on water cooling as I could only hit 3GHz with a 9700cu cooler running at full speed before the chip hit 85C

I would stick to a max of 1.5v for air cooling but more importantly stick below 65C under full load to be safe. If you have a G0 stepping Q6600 then below 70C should be safe but I would still reccomend below 65C.
 
So what is more deadly to a CPU, heat or higher voltage over prolonged exposure? I thought high volts would cause electron drift or something over the course of time...
 
Both

High temps make electron migration happen quicker and high voltage above the design voltage gives the electrons energy to migrate quicker.

Ideally you want a CPU to be as cool as possible and as lower voltage as possible.

However, saying all this the life of the CPU could be 2 weeks or 200 years and you just dont know, Over volting and over heating could reduce the life by half meaning you will get 1 week or 100 years of use from it, you just don't know which.
 
Just to clarify, I've seen several people mention to stay below 1.5v on the V.Core value. (my temps seem to stay really stable under prime95 load, even at 3.3GHz, they don't usually get over 52°c).

Now I have 2 questions.

1) Is the 1.5v value the BIOS value, or the CPUz value? CPUz reads about .250mV less then my entered bios setting).

2) I thought 1.5v was the max spec on the value range for the Q6600. Is that correct? If not, what is the max voltage spec for the Q6600.

3) ~added question~ Should I be concerned or take into account my VID voltage? How does that play into the overall Overclocking thing. I understand it is a voltage identifier / voltage regulator for the CPU. I'm just not sure how to apply this information to my OC.

I'm not trying to be a pain, I just really want to understand as much as possible what I am doing, what it does, and what I should and should not exceed. I don't just want to throw numbers into the bios and hope for the best.

Thanks!
 
1) The 1.5v is a reccomended safe upper limit and would be as read from CPUz (as long as CPUz is reading correctly). Generally I would stay under 1.55v in the bios as this should get you near 1.5v actual voltage.

2) 1.5v has been banded around for a while, above 1.5v and you need very good cooling to keep the temps under control.

3) VID voltage is the voltage intel state the chip needs to run at its default speed (Its excatly the same as you setting the same voltage in the BIOS as the CPU voltage). It can sometimes give you an insite into the overclockability of the chip but its nothing more than a guide. Other features inside the CPU can limit overclock other than the VID so it should not come into your overclocking calculations.

When overclocking, try a voltage and see if its stable (orthos for an hour), if no errors then drop the voltage a notch and re-test. When it fails up the voltage a notch and try a longer orthos / prime test, if that fails go up another notch and re-test, if its still unstable you have a different problem that is not related to Vcore, try upping the northbridge voltage 1 notch or the VTT voltage to 1.3v (1.4v max, 1.3v max on a 45nm chip). All the time check the temps when fully loaded (idle temps are worthless for overclocking). You may also need a small bump on the VTT and Northbridge voltage, I had to go up 1 setting from the dafaults to get stable at 400MHz FSB.
 
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