Overclocking my 6750: Hitting the 3.6GHz mark

Daedris

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Hey everone, I recently got a nice upgrade in terms of gcards and I wanted to minimize my bottleneck.

I just recently started OCing my cpu, and it appears I have it stable at 3.2GHz with good load temps of around 45c. I had a question about ram, though.

I have 800 mhz DDR2 RAM. I was wondering what I do now. My FSB is running at 400, and the ratio is 1:1 so my RAM is at top speed.

Do I use a different ratio to lower the speed of the ram if I push up the FSB, or do I overclock the RAM a bit and increase voltage? I have tried to do as much research on this as possible, but I am stumped at the moment.

I have a 780i SLI Mobo from XFX

Thanks for any help :p
 

iluvgillgill

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you should change the ram multiplier to 1:1 as you said above.

when increase FSB further you should increase vcore first if you experience a crash/freeze/BSOD in prime95 small ffts.

when you have pass 24hours small ffts then do a blend test for 24 hours. if during the test you got crash/freeze/BSOD then you start increase the ram voltage little by little.

but when OC you should loose the memory timing to 5-5-5-18, after all stress tests have pass then you tighten the timing to 4-4-4-12 and increase the voltage little by little untill you pass 24hours blend test again.

there you have a fully stable OCed PC.

just a little note. you will need to start to increase FSB and MCH voltage at points above 400 FSB. but you ONLY do this after increase both vcore and ram voltags and still fail prime95.

Good luck buddy!
 

Daedris

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Thanks for the reply :)

So, you're saying that I should overclock my RAM? I just wanted to make sure. So potentially, my RAM speed could get up around 900 MHZ? I want to clock my CPU to around 3.6 before calling it good enough.
 

iluvgillgill

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just keep on OC your CPU by FSB and the ram will increase simultaneously. there is no such thing as your ram's potential speed. as all parts vary on how far it can go.

but i recommend you increase ram voltage to 2V and loose timing to 5-5-5-18 when OC your CPU.
 

Daedris

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ok I am having problems getting stable at 3.6ghz now, as I crash Prime 95 after about 30 minutes of running.

I think the problem is my VCore. I set it to 1.49 in the bios but on my monitors, like CPU-Z, it's only reading at about 1.4 volts, and I think my CPU needs more. Anyone know what the deal might be?
 

Daedris

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I guess it's not my VCore. I'm not sure what's going on. Perhaps my CPU just wont clock that high?

I am currently back to 3.2ghz stable. I'd like to push it as far as it could go, but it appears that I am stuck here for now.

I increased in little notches every voltage I could find, using the save and recommend values. The only thing I didnt push as high as it could go (safely) was my memory voltage, which I boosted to 1.9 from 1.85. Is this a reason why Prime 95 could fail after a few minutes?

Any help is greatly appreciated :)
 

Lupiron

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Dunno about the memory. What prime test you doing? Small ffts for the CPU. The blend will crash after that 30 mins because the first test is a 1024 k data length. After that, it cycles to one of the most demanding tests, the 8 k blend test!

Since the 8k Small fft test is first, its like getting there, on the first series of tests! And not having to wait the 30 mins.

Also, if it was blend, it could be the ram, but for now, stick with small ffts on both cores.

You will need to look with Core Temp, or Real temp, for what either lists your VID at. 1.40 loaded would be good for 1.2750 or there abouts. A 1.3000 VID may need 1.42 volts, and a 1.3250 may need 1.45 volts WHILE loaded on small ffts to remain stable.

So take a peek at the VID and then you'll know your processors stock voltage. If its a 1.35000, good luck!

--Lupi
 

Daedris

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I always fail the small fft test on test number 4 or so after about 8 minutes.

The only thing I have NOT edited would be CPU GTL VRef boost. It's available for:

Lane0
Lane1
Lane2
Lane3

I notice that my 2nd core is the one that always fails out first in prime95. Should I be increasing the GTL Vref? If so, what do you recommend. The mobo setting is auto, but it hasnt increased it at all.
 

Lupiron

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Care to take a peek at your VID? if its 1.3000 or higher, you will need more voltage at 3.6 Ghz.

With the usual Vdrop and droop like NVidia is renown for, you'll have to use like 1.54ish to get your 1.45. Go try that in the bios, and run the test. It wont harm the processor, and if it gets past the tests, you'll know that it was voltage. if it doesn't you eliminate a common reason for failing prime, and can get to GTL modification, which is much harder, hehe!

Especially since you have no clue what it even does.

VID! Not voltage, or core voltage, etc. VID is a separate thing! Look for it.

--Lupi
 

Daedris

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My VID is 1.300 in the monitor. I have no option to change my VID in the BIOS, just the GTL Vref. So what should I do you think?

Raise CPU Core voltage to 1.54? As long as it wont fry me I'll do it :)

Thanks for the help!
 

Daedris

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From doing some looking around, VID is just something that lowers your actual core voltage from the settings you specify in BIOS, correct?

I was upping my voltages and noticed that they are always about .2 or so less than what I actually specify.

So, to get my system stable at 3.6GHz, I'll have to specify my system core CPU voltage as about 1.53+ in BIOS?

Sorry I'm such a noob, I'd just like to make sure I know what I'm doing before I push my system to the limit.

Will I be able to keep it cooled? My max load temps were 60 celcius when I had my voltage set to 1.5 in the motherboard settings.

Thanks for all the help, I REALLY appreciate it!
 

Lupiron

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VID is your set voltage for stock speed. At stock speed, and on auto, the bios vcore is set to the VID.

The lower the VID, the better for over clocking, as you get to start lower. The VID range for 65 NM chips is 1.2000 to 1.32500, with an added 1.3500.

So yours is in the upper end, thats why it will need so much voltage.

You were thinking of Vdrop and droop.

Vdrop, the initial drop in voltage from BIOS CPU voltage setting, to windows idle core voltage.

And vdroop is when you further run small ffts on all the cores, the power to the cores can once again be reduced, thats vdroop.

GTL has to do with the way your chip decides what signal to output. On intel based boards, its very rare that it will effect your over clock, unless you are already on the edge of stability.

That would be after 3.6 Ghz. :)

Your chip is fine, and you can stop the test any time your cores get to hot. Not to mention that your computer would just shut off if it go to hot. The chance of frying the chip is rare.

Just test up to 70c, if it gets over 75c, then you need to worry. Test temps are way higher than what you would ever see while doing stuff, even power gaming. That IN NO WAY Means I think 75c is good. It's not what you wanna use to end your testing. I make sure my cores dont ever get over 70c in a full 8 hour small fft session. I will go to 75c and a bit higher during testing.

--Lupi
 

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