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OMG WTF did I do wrong??? CPU way over voltage! Help Please!

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goldtna

Member
Joined
Nov 27, 2008
....so it's been a while. The last build I did, BIOS was still all blue during the first generation i7's.

So I finished assembling my new system and it wouldn't boot.
Screen says Mobo detected overvoltage.
It also says new cpu detected. Please enter setup.

So in setup, here is what I see:

IMG_20160505_003902.jpg

So my CPU, Memory, and system voltages are WAYYYY off. The scariest is the 24V on the 12V line.

WTF WTF WTF!!!! What did I do wrong?

My system:
Mobo: Asus Maximus VIII Ranger
CPU: 6700K
PSU: Corsair RM750
Video: EVGA GTX 970


I've turned off the system and turned off the PSU in case I plugged something in very wrongly.

This is my first modular PSU so maybe I plugged in the cables wrong????
1) Large ATX power cable....this can't go wrong. Only one spot.
2) CPU 4+4 pin... The PSU side of this is cable slot is right beside the PCIE 6+2 one but I'm pretty sure this is done correctly.
3) PCI-E 6+2..... I just have the video card hooked up to this... simple enough.
4) SATA and peripherals are simple enough too. CPU cooler is the only device that needs SATA power and the case lights is the only thing that requires the molex peripheral power.

Temperature readings are ridiculous too:

IMG_20160505_003954.jpg


Where could I have gone wrong???? I'm scared to power on the system right now. :(:(:(:(:(:(
 

Woomack

Benching Team Leader
Joined
Jan 2, 2005
I would check new BIOS. Readings are wrong and that's all. If there was so high voltage then CPU would be instantly dead.
 

caddi daddi

Godzilla to ant hills
Joined
Jan 10, 2012
you need to boot into bios and reset it to default, shut it down and do a full cmos reset, removing the battery, while you are in the bios, record the bios version, check that that bios version supports your cpu.
if after all this you still show all of this, download and rewrite the bios.
if the core voltage was really at 4.0v it would have toasted.

ninja'ed by woomack
 

Blaylock

"That Backfired" Senior Member
Joined
Jun 5, 2013
Location
Go Blue!
First off it's not possible for those voltages to be where they are displaying. Your PSU doesn't have a 24v rail. The highest I've seen on the 12v rail is about 12.50v. On top of that if you were able to push 4v to your CPU (you're not) it would go poof way before the post screen.

Have you tried resetting your CMOS? That's likely the problem.

Also, can you post your new system specs.

Edit: Boss started talking to me before I could finish typing. Ninja'd by both. LOL
 
OP
G

goldtna

Member
Joined
Nov 27, 2008
First off it's not possible for those voltages to be where they are displaying. Your PSU doesn't have a 24v rail. The highest I've seen on the 12v rail is about 12.50v. On top of that if you were able to push 4v to your CPU (you're not) it would go poof way before the post screen.

I will try resetting the BIOS tonight.

In terms of getting 24V... it is possible for two independent and floating banks of 12V to create 24V if the PSU was connected horribly wrongly. I kind of doubt I make such a tragic mistake.

In terms of CPU going poof! Ya, if it took 4V, then it would. I'm hoping the Mobo has a built in safe guard such that it wouldn't even power on the CPU during POST if it detects over voltage.

During BIOS setup, could it be running 100% on it's own microcontroller work even if the CPU went poof already? i.e. could my CPU be already fried?
 

caddi daddi

Godzilla to ant hills
Joined
Jan 10, 2012
no PWUFF has happened yet, the bios can id the cpu, if 2 12v rails got connected you would double the available wattage, not the voltage.
we have seen things like this before.
 

Blaylock

"That Backfired" Senior Member
Joined
Jun 5, 2013
Location
Go Blue!
Also is highly unlikely the VRMs on your motherboard are capable of providing 4v let alone requesting it.
 
OP
G

goldtna

Member
Joined
Nov 27, 2008
So I cleared the BIOS by unplugging AC power AND removing the mobo battery AND pressing the CLR_CMOS button a bunch of times.
Tried booting back up.... and this time the screen didn't turn back on. Tried it twice and no display came up.

On the third try I removed video card and plugged monitor to on board HDMI and the display came back.

The display again shows a warning that power supply surge detected and that I need to enter setup. After entering setup, the same voltages appear.

No smoke yet so I remain hopeful that my components are still okay.

ON EVERY BOOT UP (4 so far including my initial one from yesterday), The system powers up (fans start going, LEDs turn on) for about 1 second. Then everything shuts down for about 3 seconds, then powers back up. I'm guessing in that first second, the mobo detects the over voltage and shuts down. Then it reboots up in a some sort of safe mode.




no PWUFF has happened yet, the bios can id the cpu, if 2 12v rails got connected you would double the available wattage, not the voltage.
we have seen things like this before.

Two 12V supplies connected in series gives you 24V. Entirely possible but not likely.
 
OP
G

goldtna

Member
Joined
Nov 27, 2008
So my only concern was maxing up the PCI-E (6+2 pin) with the EPS-12 (8 pin).
However, I think on the modular power supply side the two are interchangable.

IMG_20160506_002157.jpg

This is a Corsair RM750. The Green rectangle what is supposed to be 2 x PCI-E 6+2pin and 1 x EPS-12. The 3 slots are identical.
The cable for EPS-12 (labelled CPU) was plugged into the red rectangle. The cable for PCI-E was plugged into the yellow rectangle. I followed the cables them selves and it looks like the cables reverse the pins properly.

I did notice that when the EPS-12 cable was disconnected from the Mobo and I tried to boot up, it doesn't do the 1 second power off, wait 3 seconds then reboot thing I was talking about so I suspected this was the source of the issue.