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Core i7 with GA-EX58-UD3R won't boot anymore after hard-crash

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August 29, 2009 3:07:30 AM


While I was doing stablility testing with Prime9.5 with all 8 threads maxing out. Core Temperatures are closing in 100C. After I got back from a bathroom break, The machine was shut-down. Subsequently attempts to reboot it, it failed to post, the fans aren't spinning and no lights on motherboard were brinking. What's my problem?

I assume that the cpu was overheating and auto shut-down or crashed or whatever. Why didn't that core i7 cpu throttling down feature kick in when overheatting?

Here is my core i7 system:

GIGABYTE GA-EX58-UD3R
Core i7-920 2.66GHz (Oced @ 3.8 GHZ)
Super Talent Chrome Series DDR3-1600 6GB
ARCTIC COOLING Freezer XTREME
Antec EarthWatts 750W
Sapphire ATI Radeon HD4350 512MB
Seagate ST3500418AS 500GB SATA2

Any suggestion to make my system post again?

Thanks!
a b à CPUs
August 29, 2009 3:14:23 AM

IMO, cpu prolly fried your mobo. it might've fried itself too
a b à CPUs
a b K Overclocking
August 29, 2009 5:02:57 AM

What are . . . er, were . . . your BIOS settings?

Had you Disabled CPU Thermal Monitor, etc, to "facillitate" overclocking? Had you tinkered with any performance settings?

I suppose you can hope your psu fried, but its likely your mobo and/or cpu.
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August 29, 2009 5:15:57 AM

did you do a cmos reset?
August 29, 2009 5:56:04 AM

BCLK=181/Uncore multiplier = x16 (NB = 3077 MHZ)/everthing else is BIOS default (unchanged)

This is 2nd core i7 I built and oc'ed. Never seen this problem before even when temp was over 100c during stress test. Usually when if it crashed, I was able to reboot again.

No, I haven't clear CMOS because I thought it has dual BIOS, why should I? It seems to have a sympton of over-heating circuit of psu. I wonder if any of you have run into this before. I am just hoping that nothing got fried, but it needs time to cool down first.
August 29, 2009 6:02:33 AM

Well see if it boots when it isn't overclocked!
September 3, 2009 4:01:03 AM

If you don't change your settings it will happen again. It probably was luck it booted in the first place. i wouldn't expect to get it going again without a cmos clear.
a b à CPUs
September 3, 2009 9:12:38 AM

You didn't manually set the voltage? I bet the reason for the high temps were because motherboards tend to be generous (to put it mildly) with the voltage when left on auto and overclocked. Also, those temps are way high. Although they shouldn't fry the CPU, they're way out of spec, and I would keep the CPU temps to 80C at most (full stress test) whenever possible. Oh, and you said you've exceeded 100C before? That's surprising - the i7 should throttle at 100C (don't ask me how I know), and cool down almost instantly when it throttles.
September 28, 2009 9:57:06 PM

This is the follow up. So the something can be noted.

GA-EX58-UD3R mobo was dead, everything (PSU, core i7, mem) else was fine because I was able to swap parts to verify that. Now I got exact the same mobo replacement and is running fine. Yes, overheating caused the failure of the mobo.

The cpu that fried the mobo was core i7 D0 stepping. Apparently, this core isn't 'good' low temp core compared with my other core i7 C0 stepping.

Idle Load
my D0 49C 100C
my C0 40C 90C

This D0 stepping core can often reach 100C during stress test(Prime95) while the C0 stepping rarely reach over 90C. Temps are measured by Core Temp.

The throttle isn't kicked in when it's over 100C. I even have BIOS warning set 90C and never heard or seen anything happend when Core Temp reports over 90C. The problem is that I really don't know the real temp the cores are, just rough guess range from reading the temps from Core Temp or Real Temp or SpeedFan.


a b à CPUs
a b K Overclocking
September 28, 2009 10:32:42 PM

Geez man you are really pushing the limits. I wouldn't push anything I own past 65° C. You realize 100° C = 212F?

How much performance are you gaining frying parts? Most games cap @ 3.4ish GHZ CPU with current graphic cards bottlenecking.

You sure you didn't disable the thermal halt stuff in your bios?
a b à CPUs
a b K Overclocking
September 29, 2009 6:42:57 AM

Running those parts that hot is not smart.

Good luck.
a b à CPUs
September 29, 2009 6:45:11 AM

What voltages and speeds are you using? Those values seem too high, and I would back off on the overclock if I were you. You should always try to keep your CPU below 80C, even in Prime95.
September 29, 2009 11:04:33 PM

ARCTIC COOLING Freezer XTREME is my cooler. I wish it had higher rpm(max=1500)
At default speed @2.66 GHZ, core temp is already at 72C during load. Don't tell me that I didn't seat cpu correctly.

The voltage is bios default. I didn't change it. cpu is oc'd @3.8GHZ. vcore=1.36v during load reported by cpu-z.

100C of core temp scares me too. That's why I am looking for reasons. I don't know whom I should trust: Core Temp, Real Temp, or SpeedFan. I somehow suspect that this particular core i7 D stepping I have messed up the temp readings of Core/Real Temp/SpeedFan. During Prime95 stress test with all 8 threads @ 100% utilization:


idle load
speedFan 35C 85C
Core Temp 50C 100C
Real Temp 50C 100C

In my BIOS, I also have lower CPU Warning Setting to 80C and it never kicks in and never warn me. So it appears BIOS doesn't think CPU temp is over 80C yet. I've tried this cpu with two mobos (same kind) and the same result. So I know it has nothing to do with mobos.
September 29, 2009 11:25:19 PM

This is a quick folow-up. I lowered my CPU Warning Setting to 70C and BIOS did warn me with beeps. At that moment, the temps were reported as follow:

BIOS=70C,
SpeedFan=85C
Core Temp=100C

a b à CPUs
a b K Overclocking
September 30, 2009 1:41:21 AM

If we can believe any temp reports, it seems the answer has to be (a) your cpu shouldn't be clock that high with (b) that cooler.

Normally, we trust CoreTemp/RealTemp/CPUID Hardware Monitor. Not Speedfan.
October 9, 2009 1:31:19 PM

Y is it so hot as u are using a best cpu cooler?
a b à CPUs
a b K Overclocking
October 9, 2009 10:13:48 PM

What thermal paste are you using man? Lets start back with the basics. No way that should run that hot at stock speeds.

You need to get your stock speed temps down before you OC IMO
November 11, 2009 3:36:18 AM

Might've popped one of your MOSFETs or something.
I have a similar setup except I run i7 920 at 3.36 GHz and there are no problems

Vcore @ 1.15

ran Prime95 for two hours without temperatures exceeding 65 C. I am using an aftermarket copper stack cooler.

Were you using the stock Intel cooler?
November 11, 2009 3:40:24 AM

Sorry about that
Thought u were using stock intel cooler.

Your AC cooler should be much better than mine, so the reason for the temperatures becomes way less likely to be faulty cooling. Maybe you should try reinstalling the CPU?
November 11, 2009 3:45:50 AM

Oh, right. You could've also suffered an incorrect overclock.

Getting to 3.8 GHz without altering some of the BIOS settings which are normally at "Auto" can fry your system.

Have you checked the DRAM voltage, the Vcore, etc? Also, there should only be a .5 v spread between the uncore voltage and the DRAM voltage. Anything more means that your system is likely to get VERY hot and die.
November 13, 2009 3:08:42 AM

Coool122, you are absolutely right about that I suffered an incorrect overclock which I wish I could know this sooner. That's the exact problem with my high core temps.

By default, BIOS has VCORE at auto mode. If you don't overclock at all, the VCORE would never go higher than 1.22v at auto mode.

However, if you ever overclock with vcore at auto mode, VCORE would automatically jump to 1.36V which is very high voltage for any air cooling even a good aftermarket cooler. The temp can reach up to 100C with 8 threads max out.
Core i7 920 has overheating protection circuitry, but this motherboard would die before CPU ever reaches its throttling down temperature level. That was the case for me. I've never ever seen or experienced CPU throttling down. However, some motherboards can withstand the heat while others overheat and die.

So don't use Auto setting for vcore because it's not necessary for mild OCing. CPU can easily be OC'ed up to 3.8 GHZ w/o ever raising its "Normal" voltage which is at 1.22V.

After setting my VCORE=Normal mode, my temperature is much lower than before while still enjoying 40% OC @3.8 GHZ. Idle=40C, Load=80C.

Why did motherboard manufacturers set VCORE=Auto by default? I don't see any benefit of doing this, but RMA'ing dead motherboards.
!