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Question about OCing Q6600

D

deadman_uk

[H]ard|Gawd
Joined
Jun 30, 2003
Messages
2,036
Quick question about the Q6600...

I want to overclock a Q6600 from it's default speed to 3GHz. The computer has a good CPU fan to keep up with the slight increase in temperature.

The computer I am on has 8GB of ram (PC2-6400/400MHz). When I change the HT in the BIOS so the new estimated speed is 3GHz and set the RAM ratio to 1:1, the RAM speed goes from 800MHz to 666Mhz. Why is this and will it affect performance more than the actual gain from the overclock?

Thanks
 
That's not right. If it's 1:1 the RAM speed should be 800Mhz. Are you setting the FSB to 333 and multiplier to 9x.
 
dwell said:
That's not right. If it's 1:1 the RAM speed should be 800Mhz. Are you setting the FSB to 333 and multiplier to 9x.
Click to expand...

Here are 2 screenshots showing the BIOS at default and BIOS with settings set to an attempted overclock:

biosdefault.jpg


biosocu.jpg
 
The reason for that is because the FSB:RAM speed ratio is changing to 1:1. To get your RAM to a higher speed, you'll need to modify the setting labeled "DRAM Speed (CPU : DRAM)" in those pictures.
 
You just need to adjust the DRAM Speed ( CPU : DRAM) so it reads DDR2 800 on the right. Here is a tip... 666 x 1.2 = 800 in terms of adjust this.

That's not right. If it's 1:1 the RAM speed should be 800Mhz. Are you setting the FSB to 333 and multiplier to 9x.
Click to expand...

Just no. Where the heck did you come up with this? Do you have any idea how this works? 1:1 means the rams runs at the bus speed of 333 and then x2 for being DDR gets the 666.
 
9 x 333 = ~3 GHz for the CPU, which has nothing to do with the RAM, yet.

Now take the 333 FSB x 2 (since it's DDR memory) = 667

Hence, the FSB:DRAM ratio is 1:1. There will be a multiplier in their someplace, the MCH or whatever, and you need to alter the "latch" so it's 2.5, not 2. 2.5 x 333 = 800, which will pooch the 1:1 ratio but it'll get the RAM running back at 800 MHz where it should be.

If that mobo doesn't offer the ability to alter the latch, then perhaps it's offering the ability to change the actual ratio, adjust that to something like 5:6 or 6:5 and it should work out so you get the 333 for the CPU and 400 for the RAM again.
 
Thanks everyone for your replies

Joe Average said:
9 x 333 = ~3 GHz for the CPU, which has nothing to do with the RAM, yet.

Now take the 333 FSB x 2 (since it's DDR memory) = 667

Hence, the FSB:DRAM ratio is 1:1. There will be a multiplier in their someplace, the MCH or whatever, and you need to alter the "latch" so it's 2.5, not 2. 2.5 x 333 = 800, which will pooch the 1:1 ratio but it'll get the RAM running back at 800 MHz where it should be.

If that mobo doesn't offer the ability to alter the latch, then perhaps it's offering the ability to change the actual ratio, adjust that to something like 5:6 or 6:5 and it should work out so you get the 333 for the CPU and 400 for the RAM again.
Click to expand...

I haven't been in the BIOS yet but am I right when I say I have to find a setting called latch or something like that and change it to 2.5? This is a must?

Zero82z suggestion seems different meaning 400x8=3.2GHz. Which would you suggest I use? Zero's or yours? anyone???

Would I have to bump the voltage up a little for 3GHz and 3.2GHz?
 
deadman_uk said:
Zero82z suggestion seems different meaning 400x8=3.2GHz. Which would you suggest I use? Zero's or yours? anyone???
Click to expand...
My suggestion was actually to use a higher RAM divider, although I mentioned that it's possible to run 1:1 with a higher FSB speed. It really doesn't matter which way you go, although if you run 400x8 you'll end up with a higher CPU speed.

As for whether or not you'll need to increase the voltage, there's no way to know either way without testing it yourself.
 
deadman_uk said:
Thanks everyone for your replies



I haven't been in the BIOS yet but am I right when I say I have to find a setting called latch or something like that and change it to 2.5? This is a must?

Zero82z suggestion seems different meaning 400x8=3.2GHz. Which would you suggest I use? Zero's or yours? anyone???

Would I have to bump the voltage up a little for 3GHz and 3.2GHz?
Click to expand...

400x8 is a nice overclock on that if you can get the 400 with 8GB. You will probably need to increase vcore, and possibly vtt, vdimm, and vmch to get there. Not by much though, if any.
 
OP shoot for 8x400 and set your vcore to 1.35V as a starting point and MCH to 1.35V. Set ram 1:1 which will be 800mhz. This will give you 3.2ghz. Ive overclocked 3 of these and only one had an issue where it would not hit 400mhz bus. Use something like Prime95 to stress it and see if its stable. Watch your temps with coretemp and see if they will stay under 70C during load. If you find your stable you can start lowering your cpu Vcore until it becomes unstable then raise it back up. You want your lowest stable voltage to keep your temps down. With 8 gigs of ram I had to get my MCH up to 1.41V to get stability but you may find you dont have an issue. If you find 1.35V on vcore isnt stable then raise it up a notch. Keep in mind passing 8 hours of any stress test does not promise stability but it will let you know your max temps and least give you an idea of stability. Because your not shooting for what I consider a high OC for that chip you can probably leave the rest of your voltages at auto accept for maybe having to increase VTT but I doubt it. These numbers are just an estimated starting point. Dont take your vcore over 1.5V and if you start getting that high really pay attention to your temps. As the user stated above you will need to set your Ram voltage to the rated voltage of your RAM.
 
I've been running my Q6600 @ 3.2GHz since the day I got it. And, I am just using the 400x8 method. My vCore is set @ 1.45 in the BIOS. (Lower according to CPU-Z)

I am using a Big Typhoon VX cooler, and have never had the temps go past 60c for any core. They idle around 40c-42c.

Also, my system is rock stable. (SuperPi, Memtest, Prime95, 3dMark, etc.)

And, I am using 8Gbs of RAM. (4x2GB Mushkin 996587. 5-4-4-12 1.8v)

As long as you don't have to kick the Vcore too high, and keep the temps low, you'll be fine at 3.2Ghz (400x8).
 
Just cool it and kick the crap out of it. Q6600's will take a beating and keep on ticking.

I'm at a rock stable 3.6 ghz at 1.45v in bios. It was on air for a long time. Just put it on water. But even on air with massive voltage 4 ghz can be had with it. 4.1 ghz has taken out two video cards with no OC on the cards. Wrote it off as a issue related to stray voltage or harmonics when pushing close or up to 1.60v. While my quad is a G0, it is a bit of a voltage whore.

Keep the fsb at 1:1 and play with other bios setting and let her rip.
 
What temps are you getting with 1.45v?

I'm testing out the OC of a Q6600 in my game machine. So far at 3375mhz (9x375) and 1.375v bios (1.352v cpuz). Temps are 66,66,58,58.
 
This Q6600 is not mine, when I have access to it again, I will overclock it from the information on this thread. Thanks all
 
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