Can't lower CPU Voltage

I'm having trouble setting my CPU voltage so it doesn't run too hot. I have an AMD Phenom X4 9850 BE CPU in an Asus M2N32-SLI Deluxe MB. Previously I discovered the auto-discover feature of the MB set the CPU voltage too high and I had to manually set it. This was stable for a long time.

My problem is I flashed to the latest BIOS upgrade and that trick doesn't seem to be working any more. CPU is supposed to run 1.05-1.3V, 61C max. Putting BIOS at "auto" for the voltage, CPU-Z reports it's running at 1.328V; I haven't found a temperature monitor for Vista 64-bit yet but the BIOS bootup says 68C, obviously too high. I've tried setting CPU voltage in the MB BIOS everywhere in the 1.05-1.30V range, even up to 1.320V, and it won't boot. I think I remember on the older BIOS, I got it to work at 1.100V. So ... I'm a bit of a noob at this, can I be doing it wrong? If I'm doing it right, what else can I look at? Or should I just revert to the older BIOS that worked? Last question, on XP there were several tools I found from Asus and others that let me manipulate these BIOS settings from within the OS; I can't find the same tools for Vista 64-bit -- can anybody suggest any? Specifically I'd like to set the MB voltage temporarily to see if it works, but if it doesn't, not have to pull the battery and set the RTC jumper just to get it back onto "auto" to boot again.

Thanks in advance.
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More about lower voltage
  1. The first thing you should do is remove and re-mount the HSF with new paste.
  2. I fixed my issue. I reverted back to the earlier BIOS and everything started working again. Either the new BIOS was slightly corrupted or it's a bad fit for my OS / CPU combo. On the new BIOS, no matter what I set the CPU voltage to, it locks up and won't boot and I have to clear the CMOS with the RTK jumper. On the old BIOS, no problem, I can set the voltage wherever I want it and the PC still boots, though if I get it low enough, Windows won't start.

    It even turns out I remembered the voltage number right, that 1.1000v is the magic number for this particular CPU. At auto setting the voltage is 1.3125v, which gives an internal CPU voltage of 1.328v and a startup CPU temperature of 62C (1 above max operating range). Manually setting it to 1.1000v, the internal CPU voltage is 1.1200v and startup CPU temp is only 50C. Same clock speed. Nice difference!

    @theAnimal, thanks for the suggestion. On this particular build, I know the cooler has good contact. I went through reseating my cooler last time when I realized I was having heat problems. As I posted above, it turned out the cause was when the motherboard auto-recognized the CPU, it was setting the voltage way too high.

    I'd kinda hoped the newer BIOS would do a better job of setting the voltage but -- SURPRISE -- it does a worse job. LOL. Good thing I don't need it, it was just a latest and greatest upgrade.
  3. CeruLucifus said:
    I haven't found a temperature monitor for Vista 64-bit yet

    Coretemp
    Speedfan
    CPUID HWMonitor
    to name a few
  4. @nukemaster, thanks. Turned out I had used SpeedFan before, so I loaded up the new version. It fit the bill, and I had Sandra from SiSoft for the internal voltage ... but both took a while to load up and report. It turned out the two free utilities from Asus, Cool'n'Quiet and PC Probe, were better for this. They're pretty simple utilities but the point is, they load faster so I can get through more iterations of setting the voltage, restarting, loading Windows, and checking the results.

    I will check out CoreTemp.

    On my main issue, it turns out the 1.1000v setting was too low -- I would get blue screens in Windows. So I bumped it up some more. Right now I'm at motherboard CPU voltage of 1.1375v which gives a CPU core voltage of 1.1520v and a startup temp of 52C. Far better than the auto setting. So far it's been stable, even playing games with SLI video cards.
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