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Q9400 Overclocking - Quick Temperature Question

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February 14, 2009 10:28:43 AM

Hello Everyone,

I read the Tom's Hardware Guide article detailing the safe temperature ranges for the Q9400 CPU that I have, and I believe it's telling me that anything below 65Cfor Tcase and below 70C for Tjunction are safe. I just want to make sure I'm interpreting that data correctly, and that you all would agree with that statement.

I currently have the CPU overclocked at 3.2GHz, and it seems to be running well. It's been running a test with Prime95 for a few hours, but I'll let it run through the evening.

My current CPU and Core temperatures are hovering around 50C +/- 2C despite being maxed out now for over six hours. Does this mean that I can / should go higher with my overclocking? I've read many examples of this CPU doing 3.6GHz, but I wanted to see what thoughts the overclocking community had regarding my temperatures and settings right now.

This is my first real attempt at this, so please forgive me if any of the above doesn't make sense. Thanks in advance for any advice!

Best Regards,
Martin Schultz

Some Stats:
CPU - Intel C2Q Q9400 currently at 3.2GHz
RAM - OCZ 4GB DDR2-1066 (PC-8500) currently at 1066
Motherboard: ASUS P5Q SE2
February 14, 2009 11:55:29 PM

If your Ram and Motherboard allow, keep going until heat is a problem.

Try to Keep Voltage down as that will affect heat the most.

Bump up the FSB by 5 or 10 and run Prime 95 for a few minutes. If it passes, bump the fsb up again. When Prime95 starts failing, bump the Voltage by .005 Volts and retest. if it passes, continue of your FSB journey.

Good luck!
February 15, 2009 1:00:15 AM

Hi Customisbetter,

Thanks very much for your advice. The temperature values on my CPU are currently well within the safe range, which makes me want to push it a little further. However, I'm running into a bit of an issue. I'm sure this is a very basic question, but as I said this is my first attempt at overclocking to any meaningful degree. I've googled on this, but I'm having trouble applying the information I've found to my particular setup...

As I said, I have a C2Q Q9400 CPU on an ASUS P5Q SE2 motherboard. This CPU normally runs at 2.66GHz, and I have it up to and stable at 3.2GHz. I'd like to raise this to 3.4 and see how it handles, but I have some settings in my BIOS I don't fully understand.

I have the option to set my FSB speed in BIOS in increments of one, ie I can set it to any whole number between 200 and 600. There's also a value for something like "FSB Strap to DRAM," for which I only have four options. By default it's set to 333, but I raised it to 400 along with the FSB speed. This allowed me to select the proper speed for my RAM, which is DDR2-1066.

When I attempt to raise my FSB speed any higher, the RAM speed of DDR2-1066 is no longer available, and is replaced with three different choices, for example DDR2-950, DDR2-1333. These numbers appear to be bound to both the FSB and the FSB strap to DRAM values. If I select DDR2-1333 (which is higher than what my RAM is rated for) my system does not boot.

What should I do? I could select a DRAM speed that is slower than what my RAM is rated for, but I don't know if that's the right thing to do. As an additional note, and this may not matter, but it appears I do not have an option in my BIOS to adjust the CPU multipler, which I know from research is at 8 by default. Any assistance would be much appreciated... this stuff is fun!

Best Regards,
Martin Schultz
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February 15, 2009 1:01:17 AM

Another side question: Would raising the voltage to my memory help overcome the speed limitation I referenced above?
a b à CPUs
February 15, 2009 1:12:55 AM

Set the ram at twice the FSB speed. IOW at 3.2GHz your FSB is 400, your ram would be running at 800. Sometimes this is called running the ram at 1:1, some motherboards call it 2.00.

My E9400 went to around 3.76GHz, FSB of 470, ram running at 940.
February 15, 2009 1:33:10 AM

You want the Ram to run "slow" so that it doesn't affect how high you CPU can clock.

That way, you can only have heat as a variable in stableity instead of overclocking two things at once.

Shen you set the Dram strap too high, it will overclock the ram. You don't want to do this yet. Do what cadder above said and set you ram slower.
February 15, 2009 1:33:27 AM

My ASUS P5Q Pro refuses to be stable above 445FSB. Keep that in mind. Also, at around 424+FSB you MIGHT have to start raising the NB voltage, but dont mess with it unless all else fails. Although we have different boards, most of the ASUS P45s OC to about the same levels, with the P5Q Pro producing some of the weakest numbers. I hate this board.
February 15, 2009 1:34:21 AM

customisbetter said:
You want the Ram to run "slow" so that it doesn't affect how high you CPU can clock.

That way, you can only have heat as a variable in stableity instead of overclocking two things at once.

Shen you set the Dram strap too high, it will overclock the ram. You don't want to do this yet. Do what cadder above said and set you ram slower.


I can vouch for this. My system will not boot when I set the ram outside 1:1 at all, when the CPU is overclocked to high levels.
February 15, 2009 2:57:16 AM

Ok, thanks for the information guys, it's much appreciated :) 

I've increased my FSB to 425, leaving my FSB strap to DRAM at 400. I'm now getting errors on Prime95 testing. What would my next troubleshooting steps be? My DRAM speed is set to DDR2-850. Thanks in advance!

Best Regards,
Martin Schultz
February 15, 2009 3:14:44 AM

Here's an image with the settings I was using. Hopefully I can go further than 3.2GHz. You can see that despite three of the cores being maxed out, the temperatures are still well within spec. The one core that's not maxed is the one that was running the failed Price95 test worker.

http://spepisodes.com/3400.JPG
February 15, 2009 3:16:43 AM

Ok, now just a add a touch of voltage and see if it stabilizes. it should go further in Prime95.
February 15, 2009 3:20:55 AM

Voltage to the RAM, FSB, or CPU? Thanks for the quick followup.
February 15, 2009 4:17:16 AM

Ok, I added more to the CPU. I added two increments from what was stable at 3.2, so it's up to about 3.8, but still got an error in Prime just as fast as the last time. The system is running, it's just that Prime is throwing errors, so I've got something wrong. Any idea what I should check next? Thanks again for all of the help.

Best Regards,
Martin Schultz
February 15, 2009 4:22:09 AM

Like I said above, youre going to need to start upping the NB voltage when you get around that FSB. These boards are a nightmare to get stable past 42x+ FSB.
February 15, 2009 4:26:06 AM

Just to clarify, I meant CPU Core voltage in my last post. I was at 3.2GHz and 1.36250v stable, now I'm at 3.4GHz and 1.37500v. I raised the FSB voltage to (corrected) 1.2v, so we'll see what happens. I'll keep you guys posted :) 

Prime just errored, so I'm going to bump the FSB voltage up another notch.
February 15, 2009 5:09:32 AM

I wouldnt recomend going any higher on the CPU voltage. These 45nm chips are not good for 1.4v.

As for your testing method, I prefer OCCT. It finds errors much faster.
February 15, 2009 5:13:39 AM

Ok, I've got it at a good stopping point for tonight, so thanks for all of your help. I'm going to go to sleep and leave it run Prime95 stress testing overnight to see what happens. Here are my ending settings for the day:

FSB: 450MHz
FSB Strap to DRAM: 400MHz
DRAM: DDR2-900
vCore: 1.36250v
vRAM: 2.20v
vNSB: 1.40v

Which puts me at 3.6GHz. Not bad for a CPU that comes as a 2.66GHz. Additionaly, temperatures still look good. Under full Prime95 stress test load, I'm getting:

tCPU: 49C
tCore 0: 52C
tCore 1: 48C
tCore 2: 50C
tCore 3: 50C

One thing I'm unsure about. During troubleshooting, I came across a recommendation that I change the timing on my RAM to 5-5-5-15. The specs for my RAM recommend 5-6-6-18. Does this change make sense, or should I put it back to the manufacturer default? Is overclocking the RAM a good idea, and is buying faster RAM going to make a big difference? One thing I noticed is that the system doesn't boot at these FSB speeds without a 1:1 RAM setting. It's running at DDR2-900 right now.

These are the questions I will be dreaming about this evening. Thanks for your help Customisbetter and Spathotan!

Good Night,
Martin Schultz
February 15, 2009 5:22:49 AM

Downloaded OCCT per your recommendation. I'm happy to let this run overnight and see what it comes up with in the morning. Will it let me know if there is some kind of error like Prime95 does?
February 15, 2009 5:30:03 AM

spathotan said:
My ASUS P5Q Pro refuses to be stable above 445FSB. Keep that in mind. Also, at around 424+FSB you MIGHT have to start raising the NB voltage, but dont mess with it unless all else fails. Although we have different boards, most of the ASUS P45s OC to about the same levels, with the P5Q Pro producing some of the weakest numbers. I hate this board.



You know for some reason I can boot into windows at 4.2GHz with the same board you have. But I can't get far into windows. I think I can get it stable but I like to be at 4GHz. You know somthing I wish you could change the FSB multiplier like you could with an AMD machine. I figured the FSB runs at a 4 multi like 333 x 4= 1333FSB now if you could change that to like a 3 multi it would be 333x3= 999FSB Image how much further these C2Q and C2D can overclock if you could change that multiplier.
February 15, 2009 6:46:43 AM

mschulz said:

One thing I'm unsure about. During troubleshooting, I came across a recommendation that I change the timing on my RAM to 5-5-5-15. The specs for my RAM recommend 5-6-6-18. Does this change make sense, or should I put it back to the manufacturer default? Is overclocking the RAM a good idea, and is buying faster RAM going to make a big difference? One thing I noticed is that the system doesn't boot at these FSB speeds without a 1:1 RAM setting. It's running at DDR2-900 right now.

These are the questions I will be dreaming about this evening. Thanks for your help Customisbetter and Spathotan!

Good Night,
Martin Schultz


Overclocking RAM is fine.

About the timings, i would leave them at stock. When overclocking you ram (past 533) you will want to loosen the timings, so 6 6 6 18 or similar.

you don't have to do this as you havn't even reached the standard speed yet.

After you are done overclocking your CPU, THEN you can start to lower your timings. It isn't necessary though as it won't equal framerates.
February 15, 2009 1:35:40 PM

Thanks Customisbetter, that makes sense. I woke up this morning to an error in OCCT, it said Error Detected on core #0, so I'm not quite there. I've already raised my vFSB to 1.4v (the maximum), and the vCore is set to 1.36250v. According to CPU-Z, it's only using 1.33v, so I don't think that's the problem. Where would you guys start looking?

Best Regards,
Martin Schultz
February 15, 2009 1:43:28 PM

Its getting to the point now where countinuing to raise the voltage gives diminishing returns, the raise in temp will not be worth the clock speed. I stopped at 3.8ghz with my X3370, I could get it to 4ghz but getting it OCCT/Prime stable was another story so I just gave up, I changed NB voltage, GTL timings, PLL voltage, memory straps, every single thing there is, I even over volted and it still wouldnt get stable, just gave up. Settled for 3.8ghz which was stable in OCCT for about 26 straight hours before I stopped it.
February 15, 2009 2:25:22 PM

Out of curiosity, I ran memtest on this system, which failed no more than a minute or two into the test. The fail range was from 0MB to 4096MB, so I think it was telling me that all of the RAM was bad. I swapped it out with a completely different set with the same result. Does this mean my board is bad, or that memtest just has an issue with it?
February 15, 2009 2:26:51 PM

Its not the memory, its how the board is dealing with the RAM due to the OC/strap. Loosen the timings. For example, try 6-6-6-16 if your memorys standard is 5-5-5-15.
February 15, 2009 2:34:54 PM

I should have specified that was at the default settings, no OCing involved. BIOS was reset to default.
February 15, 2009 4:06:42 PM

oh, then i would suspect bad ram as well...

try one stick at a time and see if the test still fails, if it does, you know which stick is failing.
February 15, 2009 5:03:43 PM

Ok, I tested two different sets of RAM and both came up bad. Then I found some posts that said memtest86 had some issues with my board, so I used memtest86+ and everything passed. Unfortunately, I don't seem to be able to keep it stable above 3.2Ghz, which is low for this CPU. I will keep playing with it when I get home tonight :) 
February 15, 2009 5:37:25 PM

alrighty, just remember that every batch of CPUs is different and that what some people get with theirs isn't exactly what you should expect.
February 16, 2009 12:56:55 PM

Thanks Customisbetter, another good thing to keep in mind. I'm up to 3.4GHz and seemingly stable - OCCT ran all night without a problem and I'm letting Prime95 run during the day today. I know Spathotan said he doesn't like this board (ASUS P5Q SE2) for overclocking. Would I get better performance with a different board?

Thanks again,
Martin
a b à CPUs
February 16, 2009 3:26:15 PM

3.4GHz means you are running your FSB at 425. Your CPU may or may not be able to go higher, but if the CPU was a really good one you would have to be able to run your FSB at well above 450. There are boards that will do it.

I'm not sure you could tell that much difference between running your CPU at 3.4 vs. running it at 3.6 or 3.8, but that's up to you.
February 16, 2009 7:21:20 PM

Cadder,

That's what I'm thinking. It may not be worth the trouble to try to go any faster... I'll see what I'm in the mood for tonight, but before I do any more OCing I'd like to actually use it for a bit :) 

Best Regards,
Martin Schultz
February 17, 2009 12:22:14 AM

I say keep it the way it is. You computer is now faster than 99% of the PCs built in the world. Take some time to enjoy being on top before worrying if you can make it a few percent faster. ;) 
!