High CPU Voltage = Reboot

johan851 · Jun 7, 2004

I was wondering if anyone else has this problem (or maybe a fix for it). Whenever I raise the CPU voltage past 1.85, I get random restarts in Windows. It usually happens when load is applied to the processor - Prime95, Sandra, etc. It happens soon at 1.9v, very soon at 1.95v, and usually right when Windows loads up at 2.0v. I know my cooling is adequate, I've taken this processor and cooling past 2v before on my Abit board. I think this is a motherboard issue. Can anyone help?

chaosdriven · Jun 10, 2004

johan851 said:
I was wondering if anyone else has this problem (or maybe a fix for it). Whenever I raise the CPU voltage past 1.85, I get random restarts in Windows. It usually happens when load is applied to the processor - Prime95, Sandra, etc. It happens soon at 1.9v, very soon at 1.95v, and usually right when Windows loads up at 2.0v. I know my cooling is adequate, I've taken this processor and cooling past 2v before on my Abit board. I think this is a motherboard issue. Can anyone help?

Can't help you with this, but I have noticed exactly the same with my other rig ( Epox 8RDA+), so I am inclined to think that this may rather be processor related. The DFI based system is running fine at 1.95 vCore.

johan851 · Jun 10, 2004

I heard something about this somewhere else. Apparently the voltage regulator on this board is only supposed to go to 1.85v, and DFI did a voltmod to make it go higher. One way to get past it is to do a voltmod yourself and keep the set voltage to 1.85v - basically bypass DFI's voltmod.

obsolete · Jun 10, 2004

Anything above 1.9V has never worked for me using "MULTIPLE" DFI LP U-B boards & using a digital multimeter to read the actual volts.

I tried several different bios's just for kicks & all of them showed that anything above 1.9 volts stays at 1.9 volts.

I have had the same (similiar) problem as you. If I set the vcore to 1.95 or 2.0 it will just freeze. The only thing I can recommend is doing the volt mods so you can set the vcore to whatever you want.

johan851 · Jun 10, 2004

Thanks DFI...

obsolete · Jun 10, 2004

Hey! Whats that suppose to mean?

hangten · Jun 10, 2004

Some chips can't handle higher voltage.My 1800+ tbred B becomes unstable at anything over 1.93 even lowering the MHZ won't work. My 2100+ tbred B will handle 2.1 without any fuss and run at 2400mhz. Tried on an ASUS and DFI. The Asus well modded seems to be more stable because of the voltage mod. I would think that the DFI NFIIB would do the same if modded. I love my DFI and sold my ASUS. My advice is to buy a better chip.

Highlander · Jun 10, 2004

The DFI's seem to have dodgy rails at high Vcores, if you look in summit like MBM, you might notice a large amount of fluctuation (not going to be 100% accurate as its sensed)
One way might be to perfom some Vmods on the board, this should help get the rails stable.
Other than that, do you have the vreg mosfets sinked, with adequate cooling?

Cow2kie · Jun 11, 2004

My lanparty does 2v just fine. Maybe some mods might help you out. Either that or get a new one.

johan851 · Jun 12, 2004

Hey! Whats that suppose to mean?

I mean it's kinda stupid of DFI to offer 2.0v in their BIOS when they haven't correctly implemented it in hardware.

obsolete · Jun 17, 2004

I mean it's kinda stupid of DFI to offer 2.0v in their BIOS when they haven't correctly implemented it in hardware.

Ahhhhhhh.........Ok, thought you were calling me a DFI support type person by how I responded to your thread or something.........Sorry for the delay, lol. Been busy, hard to keep up on posts at times.

I 100% full agree with you! Also, I think 2.0v may work just fine with some boards, but I bet if you get the multimeter out you will find that the board is not actually putting out 2.0 volts.

So where 2.0v may seem fine & may actually help your OC. I'd like to see someone verify that the board is in fact putting out 2.0v & preferably to confirm this with a multimeter. Without mods....

-ºb§

blaze · Oct 1, 2004

Hi!
This is my firs post here. I have exactly the same problem as johan851 and it's driving me mad. Has anybody found a solution for this? Or does somebody have any other ideas what I could try? Your help will be immensely appreciated.

B

Sentential · Oct 1, 2004

My NF7 does the same thing. Anything over 1.875v wont boot....like at all :temper:

enduro · Oct 1, 2004

^ Really? That's odd. On mine I can take it to 2.05 just fine. Not that it helps that much. I have to jump from 1.9 to 2.03 to gain any noticeable stability. I have noticed that every once and a while I'll get a black screen and then the siren when booting up after a save and exit. But that is really random. I rarely take it up that high though, because for practical uses, on air, anything over 1.9 shouldn't be run 24/7 anyway. My summer temps get way to high to run 1.9+V during the afternoon.

johan851 · Oct 1, 2004

blaze:

I heard something about this somewhere else. Apparently the voltage regulator on this board is only supposed to go to 1.85v, and DFI did a voltmod to make it go higher. One way to get past it is to do a voltmod yourself and keep the set voltage to 1.85v - basically bypass DFI's voltmod.

Since the voltage regulator is only rated to 1.85, everything higher causes crazy vcore fluctuation and reboots. There is no solution short of doing a voltmod yourself.

blaze · Oct 3, 2004

Are you sure that a voltmod would help? I’m asking because I’m considering selling this board and buying a new one. And for that it would be nice if it were RMA-ble. But in any case could you point me in direction of a good guide for the voltmod?
Thanks!

B

Samurai Jack · Oct 3, 2004

Your problem may be that bios is seeing to high of a temp, then it shuts the comp down for pertection. There may be settings to ujust this in bios. Its more than likely not shutting down because the curcuit failure.

This happens on my board when temps get to high, I got better cooling & it quite doing this & I can turn my voltages all the way up.

Also your Power Supply can add to this problem if it can not supply enough power.

SJ :sn:

Nico3k · Oct 3, 2004

I had the EXACT SAME THING.... it was my power supply. I had a 350watt antec TP and at 1.95 I get reboots when I give it a heavy load.
Got a new power supply and never had a problem again after that.

Get a multimeter and check your lines. Also check what MBM says under +12V when you are under load.

blaze · Oct 3, 2004

I'm pretty certain that it's not my psu. And that is not just because I just bought a new one . I tried removing GPU mod and downclocking my Radeon, but the problem didn’t go away. As for the temperatures and voltages: Click!
Oh and I tried measuring voltages with a multimeter and the results were even better than with MBM. And I’m always under load (F@H).

B

johan851 · Oct 3, 2004

Like I said, it's a problem with the motherboard. I could push to 2.0v and beyond with my NF7-S, but with this DFI, like so many others, going past 1.85v causes vcore fluctuation. I have a Fortron 530w, and my rails are spot on when measured with a DMM. MBM5 is completely innacurate for checking rails, and I would recommend against using it. My DMM says 12.05 or so, and MBM5 reads 11.61v. It's not really the fault of the program, but the fault of the onboard sensors.

As far as I know a volt mod is the only way to get past it. It's a physical problem with the board's circuitry, not a BIOS issue or anything. Also, the voltmod only works when you set 1.85v or below in the BIOS. Above that, even with a mod, produces the same instability.

High CPU Voltage = Reboot

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