Stabilizing Vcore on NF7 and HEC 475W.

Runner30

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Apr 3, 2004

• Jun 5, 2004

• #1

I'm running XP-M 2500 on NF7 at 1.9V which is 1.82 +/-0.02.
It even drops to 1.79V, and then prime95 fails

Any way to stabilize the voltage?

Thanks.

 

Mr.Radar

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Dec 26, 2003

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Currently on a silent vacation from overclocking.

• Jun 5, 2004

• #2

The MOSFETS on current NF7-S's suck. Try putting some heatsinks on them, or if you can, return the NF7-S and get a DFI Ultra Infinity.

 

ZachM

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Oct 11, 2003

• Jun 5, 2004

• #3

Measure the PSU's 12v and 5v rails with a multimeter while they're under load. If your PSU is staying in spec, sink your mosfets. A small fan over them also helps from what I've heard.

 

OP

Runner30

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Apr 3, 2004

• Jun 5, 2004

• Thread Starter
• #4

Thanks for the replies.

What do you mean by "in spec" ?

I don't have a voltmeter, software shows not more than 5-10% clearance from 12V and 5V.

I'm not sure cooling MOSFETS will do any good.

Maybe there's something that could be made with the PSU itself?

 

Fallen Phoenix

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Jul 22, 2003

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Odessa Tx

• Jun 5, 2004

• #5

The PSU is not the problem, it does the same thing with my Fortron and with my friends Antec. Mosfet cooling seems to help, I don't have sinks on mine but a fan blowing air over them, doesn't do much but it is noticeable.

 

ZachM

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Oct 11, 2003

• Jun 5, 2004

• #6

I meant if your PSU voltage on the 12v and 5v rails are close to 12 and 5 volts, then it's a mosfet problem. I was thinking possibly your power supply is weak and not giving enough volts to the CPU.

NF7s do tend to undervolt, but cooling your mosfets could help keep it from fluctuating.

 

pelikan

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Jan 22, 2003

• Jun 5, 2004

• #7

I don't know if I believe this NF7 vcore fluctuation as seen in my software monitoring. According to MBM5 all my rails and vcore fluctuate, but my digital multi meter tells me I have no fluctuation in my rails or vcore. I've read the rails from the molex and off the board and the vcore from the mosfets.

 

Fallen Phoenix

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Jul 22, 2003

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Odessa Tx

• Jun 5, 2004

• #8

Mine just undervolts, I've taken everything else out of the case but RAM, CPU, Vid card just to be sure it's not a power supply issue. I've got a 350Watt Fortron PSU.

 

pelikan

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Jan 22, 2003

• Jun 6, 2004

• #9

I've got a 350W Fortron too. My MB is not actually undervolting.

 

Turd Furguson

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Jun 1, 2003

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Ashland, KY

• Jun 6, 2004

• #10

Your Vcore will always fluctuate. All it takes is putting a little bit of a strain on your PSU and the resulting load will send a small backlash thru the PSU to the other rails cause a small infraction of fluctuation. This is what I seen while performing logic controls for my degree. Even with a huge amperage on the rail there is still going to be a fluctuation once some operation is being performed.

 

OLMI

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Jul 22, 2002

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San Diego, CA

• Jun 6, 2004

• #11

Turd Furguson said:

Your Vcore will always fluctuate. All it takes is putting a little bit of a strain on your PSU and the resulting load will send a small backlash thru the PSU to the other rails cause a small infraction of fluctuation. This is what I seen while performing logic controls for my degree. Even with a huge amperage on the rail there is still going to be a fluctuation once some operation is being performed.

Click to expand...

Slap some heatsinks on there just because it's cool anyways...

 

Turd Furguson

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Jun 1, 2003

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Ashland, KY

• Jun 6, 2004

• #12

But yes I would put some on there. IC's shouldn't be that hot IMO. Heat ruins voltage stability for mosfets.