Would like to overclock my E8400

G.SKILL 4GB (2 x 2GB) 240-Pin DDR2 SDRAM DDR2 800 (PC2 6400) Dual Channel Kit Desktop Memory Model F2-6400CL5D-4GBPQ
Corsair 450vx
Thermalright Ultima-90

At stock speeds my idle appears to be 30C according to Core temp and Real temp.

I have never overclocked before. How do I do it? Do I need faster memory?
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More about would overclock e8400
  1. No mem is fine just use the mem multiplier to keep the mem close to 800. up the front side bus (FSB) till it acts funny. I had an e8500 at 3.8 so you have allot of room. Have fun.

  2. Thanks! Going to give it a shot now..
  3. Read a guide first if you have no idea how to overclock. Something like this

  4. Thanks leeno, I have skimmed some guides like that and I think I got the general idea (hopefully!)

    This may be a dumb question, but is "CPU Host Clock Control" the correct item to adjust (FSB)? The bios says if I enable this I should set CPU voltage control to auto (it's on normal now). Is that right?
  5. Every motherboard brand has different naming schemes for their bios so its hard to tell. I think the stock FSB on the e8400 is 333mhz, so look for that. And CPU voltage should be set to manual, at least imo.
  6. Here's a screen shot of the bios I found on the web. http://imageshack.us/f/116/image002gv2.jpg/

    My settings are:
    CPU Clock Ratio: 9x
    CPU Frequency: 3.0, 333x9 (this is just an info item, not a setting to change)
    CPU Host Clock Control: disabled
    CPU Host Frequency (Mhz): 200 (changeable upon enabling previous setting)
    PCI Express Frequency(Mhz): Auto
    System Memory Multiplier: Auto
  7. Your FSB is CPU Host Frequency(Mhz)
    Set your PCI Express Frequency(Mhz) to 100mhz
    Set your System Memory Multiplier to whatever keeps your Ram speed, Memory Frequency(Mhz), near 800.
    And set your Ram Voltage to whatever your stock ram specs says they are, 1.8v to 2.1 for DDR2
    Then you can start bumping the FSB until it becomes unstable, when it does you can bump the voltage, and start over with the FSB again. I believe the max (safe) voltage is 1.365 but you should shy away from maxing out your system if you want it to last a while.
  8. Thanks a lot. The only thing I am wondering now is why the FSB reads 200 right now. Shouldn't it read 333?
  9. Forgot to mention that you should turn off C1E function and EIST Function. This may be why its showing up as 200, if not then maybe you system was underclocked
  10. I followed the suggested settings in post 2 of this thread: http://forums.guru3d.com/showthread.php?t=257966

    Then I ran OCCT and it says error detected on core 0 after under 2 minutes. What do I do now?

    Side note, all programs are still saying 30C idle and 37C load on one of the cores. Can I trust this reading? The other core sensor doesn't seem to work, stuck at 38.
  11. Errors mean that you don't have enough power(voltage) to the cpu.*

    What Programs are you using? I use Core Temp and HW monitor.

    Edit: increase your voltage*
  12. Ok, I upped the cpu voltage and left all other voltages the same. Started a test, and got a BSOD. Wow! Haven't seen one of those in a while.

    Upped again to 1.3 in bios, but occt is saying vcore is hovering at 1.23-1.26. Are these the same thing, and actual voltage is just lower than what you set in bios?

    6 minutes into test, so far so good. NOW the temps are kicking upward finally, got up to 47C. It seems the other core sensor also starts working once you get past 38C. Using core temp, real temp, and occt to monitor temps.
  13. the lower vcore you see is from Vdroop
    too lazy to explain so here's a site to read on it lol.

    Edit: remember to not go over 1.3625v and what Ghz are you going for with that 1.3v?
  14. Thanks for the info. I'm at 3.6 (400x9). Might just leave it there long term.
  15. Well, I left it to do a 1 hour test with OCCT and it detected an error with 1 second left! Does that seem bizarre? Do I up my voltage again, or could something else be the problem? I got the impression that the voltage would be easily high enough at this clock speed.

    Once I get things stable, is alright to leave it OC'd for good? I've had this processor for almost 4 years now but never OC'd it until now.
  16. to be considered stable, you'd have to run the stress test at least 24 hours.
  17. 24 hours with no errors? Should I up the volts more and try again?
  18. yes, but where are you at on the voltage?

    also is your ram near the the 800mhz speed?
  19. RAM is right at 800 (400x2)

    CPU voltage is 1.3. From what I understand, I might have to tweak other voltages as well?
  20. you may need to increase your northbridge voltage, tho i don't know what it is called in your bios.
  21. Sigh. Some good points, some misconceptions, and some wrong things. It's time for some adult leadership. :)

    Shadow's Gigabyte motherboard OC guide:
    It's for an EP35-DS3L.

    Go through the guides. Then take your core voltage off Auto and set your memory voltage to factory recommended values. Change the System Memory Multiplier from AUTO to 2.00. Then when you increase the FSB, the memory clock will rise in in proportion with it. At an FSB of 333 MHz, your memory clock should be at 667 MHz.

    You are at 3.6 GHz (400 MHz X 9). That is a 1:1 FSB:RAM ratio (DDR2 RAM, remember?). Any higher and you outrun the capabilities of your RAM. You can generally make DDR2-800 RAM run at -1066 speeds. Increase the RAM voltage to 2.2 volts. Don't worry, that is a safe voltage.

    Judging ferom the part number of your RAM, your timings are something like 5-5-5-15. Relax them to 6-6-6-18. That should give you enough headroom to push your FSB higher.

    Core2 CPU's are rather insensitive to changes in RAM speed and timing. These changes will have an unnoticable on system performance.

    Intel's max recommended voltage for the 45 nm CPU's is not 1.3625 volts. It is 1.45 volts.
    http://download.intel.com/design/processor/datashts/320467.pdf page 17.
    You can learn all kinds of neat things poking about the technical documentation. :)

    Turn off EIST, work out your OC settings, then reenable EIST. There's no reason to let the CPU run at full speedwhen it is idling.

    Compared to the quads, the thermal load of the E-series CPU's are relatively low. You will not need a great cooler to keep your core temps under 70 C.

    There has been a lot of discussion about how long to stress test a system. Consensus is that 6 - 8 hours is enough. It just depends how important stability is to you. I stress test for 24 hours. I used to test for 12 hours. Then one day I left a system running over night and idscovered that Prime95 failed at 15 hours. Made changes and the next night it failed at 18 hours. Made more changes, and I let it run 3 days. I then decided that 24 hours is enough.

    The P95 small fft's test stresses the CPU. The large fft's and blend tests work the memory harder.

    My present systems:
    GA-EP45-UD3P | Q9550 OC'd to 3.6 GHz (425 MHz X 8.5) C3 stepping :(
    GA-EP45-UD3L | Q6600 OC'd to 3.6 GHz (400 MHz X 9) G0 stepping :)
    GA-EP35-DS3P | E7500 OC'd to 4.1 GHz (372 MHz X 11)
    GA-G41m-ES2L| E6500, OC'd to 3.87 GHz (352 MHz X 11) - limited by motherboard

    All are 24 hour Prime95 stable with EIST enabled.
  22. Thanks again for the help.

    Did I get that right that I can overclock my RAM to 1066? I am probably going to leave it at 800 anyway. It is at 400x2 right now with stock voltage and timings, and I ran memtest and everything was fine. I have lowered the CPU multiplier to isolate the FSB. Got an error and upped the voltage 0.1 and now running it again. After I get that where I want it, I will do the CPU. Am I on the right track?

    One other question, what is the "uncore" clock? I read that I am supposed to set this to match the memory clock by a certain ratio but I don't see any other clock setting.
  23. G'byte doesn't use an "uncore" clock.

    Run the internal multiplier at max. You gain very little by trying to maximize FSB freq. You also gain very little by trying to overclock your RAM. Maintain your FSB:RAM ratio at 1:1.

    With what I suggested, you can probably run your RAM at -1066 speeds. I suggested that because if you want to reach 4.0 GHz, youwill need to run your FSB freq at 445 MHz. That means that your memory will be running at DDR2-890 speeds, well above its rating.

    In my Q9550 system, my RAM ran at DDR2-850 without tinkering with the settings. But when you are pushing component limits, stability becomes really important.
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