Can't raise CPU voltage on Maximus w/6850

I've just started my overclocking foray with my Maximus Formula, bios 907 and an e6850. If I leave the CPU core voltage on auto I can up the FSB, currently @400. My mem is running 2.2 volts and is running @1066 5-5-5-15 2t and I've been able to change all other settings seemingly without impact.
If I change the core voltage (only tried options higher than 2.8 since that's what mobo runs @stock) the system refuses to boot. Has anyone seen this before? The system is currently choosing a core voltage of ~1.32v.
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  1. Uhh...2.8V? for the cpu? That's really high, if that' what you meant.
  2. Oops, was sposed to be 1.280v
  3. What multiplier are you using? Chances are the vcore wasn't high enough.

    And is the 1.32V in the bios or CPUZ?
  4. CPUZ (I know I know, but it's been reading withing .001v of the bios)...I haven't made it back to the bios yet while I'm trying to determine if 400mhz is stable because until I flashed the bios I couldn't get it over 390mhz.

    Multiplier is still 9.

    I noticed that when left on auto the vcore would stay at 1.280 all the way up to 390 mhz, and if I tried to raise it to anything up to 1.50 the system refused to boot. Is not posting a typical sign of vcore undervoltage?

    Something I just thought of, this is the first attempt over 390mhz with the new bios, all previous attempts were made on the original Maximus bios. The vcore thing still holds true though, I'm just able to leave the vcore on auto and actually make it into Vista. I think the old bios was not upping the voltage when left on auto.
  5. Did you raise the NB voltage? Did you raise the FSB voltage? Try that first, going in increments of .1v.
  6. After I ran into this prob, I decided to try the settings from another e6850 user with the Maximus mobo. I know that each CPU is different, but his setting had 450 mhz fsb, and I was trying for 400. I used his/her settings for voltages, NB: 1.55, SB: 1.1, FSB Term: 1.53, with the CPU voltage in increments up to 1.5 (they used 1.57). I've still got all voltages except CPU set to the aformentioned and the system is running fine @30 degrees CPU and 45 degrees NB.

    So yes, I've tried raising all voltages at some time or another, in small or large increments. The system seems to be ok with any change except cpu voltage.

    Maybe I'm just tired from reading flame wars and should sleep on it...
  7. With the current 907 bios I seem to be limited to running 400 mhz FSB. Since I can't adjust the CPU voltage, any FSB above 400 mhz on the auto setting seems to think that 1.320 v is enough, but I Vista hangs upon loading every time. Any adjustments to other voltages works ok, but I still can't get Vista to load.

    Also, I've noticed that since the last bios upgrade the temps listed in the bios are way off for the CPU. It usually reads 4-6 degrees C for the CPU; I've even seen it at 0 before. While I'm on the subject of temps, what is the motherboard temp measuring on this board? It's usually reading between 30 and 45 degrees, but my N.B. and S.B. are anywhere from 30-60.
  8. If you're not using the proper RAM:FSB ratio, that could also cause your system to not post.
  9. Yeah, I can see how that would keep me from posting, but I've tried it with the RAM @ voltages from 1.8 to 2.2, timings from 5-5-5-18 to 5-5-5-18, Clock twister on auto, light, and strong, ratio of 1:1, 5:6, and whatever else it offers. I can change the RAM settings and see the effects, whether it's better/worse performance, or post/no-post and boot/no-boot.

    Seems that I even set the system back to stock, 333x9, RAM @800mhz 5-5-5-18, all settings on auto 'cept CPU voltage. When I changed it from auto (runs @1.280 stock) to 1.280 system wouldn't post. This has carried through the original 4XX bios to the current 907 version.

    Oh well, I guess I'll be happy with a 600 mhz O.C.
  10. That is strange. I would RMA the motherboard honestly. Unless you are happy with 3.6. 3.6 is pretty fast, and honestly, is very close to the max for what you're going to see with the 6x50 series with air cooling. I tried 3.8 on my 6750, but could only get it to even post with almost 1.6v. No way I'd leave it there 24/7. I'm already slightly uncomfortable at 1.425 at 3.6. My system runs nice and cool tho. CPU only gets moderately warm if I'm hammering on it.

    Try stock speed at 1.3 and 1.325 vcore. If it will pass POST there, then you might be around the same ballpark as I was. Anything higher than 3.6 and you might have to pump the hell out of the vcore, and it's just not worth it.
  11. I was messing around with voltages last night. I lowered the N.B. voltage down to 1.46 because all my temp sensors were telling me the N.B. was running at 56 degrees even at idle. But lowering the voltages .2v didn't affect the temp, I was still able to run 3 rounds of 3dmark06. Also, the S.B. temp was @49 degrees. Whatever the motherboard temp is (?) it's showing ~47 degrees most of the time, while the cores are usually between 27 and 37 degrees. I am happy with the performance @3.6 ghz so I think I'll try to get the system as stable and cool as I can at that speed, then try for higher.
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