Overclocking E8400

yayman

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Hey guys I am trying to overclock my e8400 on a xfx 750i sli mobo with 4096mb dual channel ddr2 ram. The overclocking section in my bios is very poor and unlike others that I have seen. I am particularly confused on the CPU voltage. In my bios it says the range is from CPU default to .3000v. It isn't even in the 1's range...I don't know why it's a decimal. My CPU FSB clock is 1333 mhz right now and definitely want to boost that up. Any suggestions?
 

yayman

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I don't know CPUID shows my voltage currently as 1.08...in bios it's at 0.0000 but i can extend it to .3000. I don't know if the max CPU voltage is 1.38 that doesn't make any sense
 

darkguset

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That probably means +0.3V

the default voltage range from Intel is 0.8500V-1.3625V

So, if your motherboard is driving the CPU at 1.26V by default, with the +0.3V it would work at 1.56V. You need to find out what is the default voltage of your CPU. If you can't see it in the BIOS, boot into Windows and run a program like Lavasys Everest and look for the CPU info.
 

darkguset

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It all depends on the chip. Same models can do different speeds at different settings. In general though eg. in my case, my E8400 does 4,050MHz at 1.445V
So you could probably do 3.8GHz at about 1.38V i guess.
 
The default voltage range for the Wolfdale chips is 0.8500V-1.3625V. 1.3625 volts is Intel's recommended max voltage. 1.45 volts is Intel's recommended "do not exceed" voltage. Forget the "nominal + .300 volts".

So, first, restore factory default values. Does your system now boot and run? If not, fix that first.

Now, I'm working from memory here because I retired my eVGA 680i board years ago when eVGA told me that it wasn't going to be Yorkfield compatible. (They were right. It wasn't compatible.)

So, at stock, you have a 333 MHz FSB frequency and a 1333 MHz FSB clock. Take your memory settings off Auto and set the memory clock to Linked or set it to 667 MHz. Set the RAM voltage to whatever the factory recommended values are or run them up to a max of 2.2 volts.

Now you can start increasing the FSB.

I couldn't push my 680i chipset past 442 MHz, even at the cost of really high MCP temps (<85 C).

Use google to find an OC guide for your specific motherboard. Something else you can do is to look for 680i OC guides. The nVidia 700i series is simply a 600i series modified for Yorkfield compatibilty so the same BIOS settings will work.
 

yayman

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Ok just got my first successful overclock....the CPU is running at 3.375ghz with voltage of 1.192....the RAM is set at 667mhz with 5-5-5-15....im a little worried to go any further without guidance....what is a safe yet good max for both CPU and RAM settings?
 

darkguset

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For the CPU it depends on the cooling. Are you using stock cooler or 3rd party?

Look for the temperatures that load does not exceed 65oC. For the voltage i wouldn't go above 1.46 without water cooling.

I am using a 120TRUE heatsink, hence my settings are quite safe.

For your memory, the default voltage should be on the sticker. DDR2 usually operates in the ranges of 1.8V-2V. Your RAM of PC6400 means it is designed to run at 800MHz (you are running it at 667MHz), which means you are not using its full potential. In your case i would try these settings: 4-4-4-12, at 400x2 (800MHz) at 2V. If you get memory errors, BSODs, etc, then try upping the voltage to 2.1V then 2.15V if necessary. Don't go further than that if you are not familiar. If that does not solve the memory problems, drop the timings (5-5-5-15). But i reckon at that speed (800MHz) 4-4-4-12 should be easy.
 

darkguset

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Leave your CPU multiplier as is. What you need to change is the FSB (bus speed). Yours is at 385MHz right now.

Change it to the nice round "400MHz" and you will get:

CPU: 9x400=3.6GHz
RAM: 2x400=800MHz
FSB: 4x400=1,600MHz

For that 3.6GHz on your CPU, you might need to increase the voltage a bit. But try as is first and see if you get any problems. If not, leave as is.

If you plan on overclocking more than 3.6GHz you should invest in a better cooler.
 

ace700

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if you want to overclock the cpu first increase the multiplyer first to see if the chip can hanndle the temperture or the load barings before i start on increasing the cpu votage. The con on increasing the cpu votage could cause the cpu to start on fire due to too much votage going to the cpu or blow out the conductors or the chips on the motherboard...
 

ace700

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you cant ask people to tell you what settings you should use. I will decrease the timings from the top and work my way down by lowering the number down by 1 to see if it incearse the ram speed and memory. After I lower 1 setting down by 1 i put it through a stress test for about 2 hours too see if the computer can handle the load
 

yayman

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well I wanna get the CPU voltage down first before the RAM setting....or should I do the other way around? my default cpu voltage is 1.08 and the max is 1.38...also about the RAM mem clock...I've ppl say to set it at its lowest value and others say set it normally...to get my 3.3gz oc I have it at 667 FSB should that increase as I increase the CPU FSB?

Also should I enable or disable spread spectrum and Intel EIST?

I've been experimenting with raising the FSB clock by 5 increments at a time....I can't even seem to get it at 1550....it's running at 1505 with 1.192v....as a generally rule of thumb does the voltage increase as the fsb clock increases??
 

ace700

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well I wanna get the CPU voltage down first before the RAM setting....or should I do the other way around? my default cpu voltage is 1.08 and the max is 1.38... I would leave it at stock CPU voltage first and start decreaseing the timings of the ram till it becomes unstable. I would do a stress test every time I decrease the timings by 1 and check to see what my memory reads. If you memory starts to get lower then i start to increase the voltage by .01.. keep in mind if this is the first time and you have some spare computers laying around i would test it on them first before doing it on the computer you use every day.

also about the RAM mem clock...I've ppl say to set it at its lowest value and others say set it normally...to get my 3.3gz oc I have it at 667 FSB should that increase as I increase the CPU FSB? Yes when you increase the FBS it will make the CPU faster but you should do stress tests on every 5-25 FBS increments to see if it will be stable on heavy loads.

Also should I enable or disable spread spectrum and Intel EIST? I will disable Spread Spectrm and Intel EIST because if your stock cpu says 2.7GHZ the reading will be like 2.0GHZ when the they are both one.

I've been experimenting with raising the FSB clock by 5 increments at a time....I can't even seem to get it at 1550....it's running at 1505 with 1.192v....as a generally rule of thumb does the voltage increase as the fsb clock increases? Yes when you increase the votage of the cpu you will get more speed but if you increase too much your cpu will blow.. I don't even bother with increaseing the cpu votage.
 

yayman

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Thanks for all the advice guys....I am getting the hang of it and have been able to increase a little bit...its running at 3.4ghz now with an idle temp of 41c....now can anyone suggest a good stress test program to get?
 

yayman

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hmm memtest was good but to my surprise when I was gaming last night my system froze several times and this was about 2-3 hrs in....so I lowered the settings and just recently ran Intel Burn Test with FSB at 1500 and the RAM FSB at 667....the test was succesful (it ran it 5 times at max RAM and it completed in around an hour)....my question is how accurate is the test?