Computer freezes irregulary

Question

My computer freezes irregulary mostly while watching videos.

• I can reproduce the problem when I remove all hard drives and boot from a memory stick with an linux on it.
• To stop it I have to push the power button for a while. (A short click doesn't help)
• It can take hours for the computer to freeze but when I start watching a video on youtube it will only take minutes to the next crash (But eventually he allways freezes within a day)
• Another confusing thing is that when the computer freezes it takes the router down...

Computer specifications

• Motherboard : ASUS P5N-T Deluxe
• Processor : Intel Core 2 Quad Q9300 @ 2.50 GHz (4 Cores)
• Memory : 4096MB
• Graphics : ASUS Nvidia GeForce 9600 GT 512MB
• Monitor : ASUS VS247

Memory

I've run a Memtest86 v5.01 and it run 12 passes with zero errors.

Processor

To test my cpu I've run the following bash script.

fulload() { dd if=/dev/zero of=/dev/null | dd if=/dev/zero of=/dev/null | dd if=/dev/zero of=/dev/null | dd if=/dev/zero of=/dev/null & }; fulload; read; killall dd

All 4 of the cpu cores where a 100% busy for 10 minutes and I experienced no freeze. (But one minute after I've stoped the script)

Graphics card

I've bougth another graphic card (ASUS GT-210 Silent (1GB)) replaced the old one and still can reproduce the freeze.

Motherboard

I searched on the motherboard for damaged capacitors but could not find one.

Hardware temperature, fan speed, voltage

Psensor is running on the linux and the freezes occur while the temperatures are in the regular area.

sensors tells me the following (almost at the time of the crash).

acpitz-virtual-0
Adapter: Virtual device
temp1:        +40.0°C  (crit = +75.0°C)

nouveau-pci-0400
Adapter: PCI adapter
temp1:        +71.0°C  (high = +95.0°C, hyst = +3.0°C)
                       (crit = +105.0°C, hyst = +5.0°C)
                       (emerg = +135.0°C, hyst = +2.0°C)

coretemp-isa-0000
Adapter: ISA adapter
Core 0:       +55.0°C  (high = +80.0°C, crit = +100.0°C)
Core 1:       +56.0°C  (high = +80.0°C, crit = +100.0°C)
Core 2:       +53.0°C  (high = +80.0°C, crit = +100.0°C)
Core 3:       +49.0°C  (high = +80.0°C, crit = +100.0°C)

atk0110-acpi-0
Adapter: ACPI interface
Vcore Voltage:       +1.30 V  (min =  +0.85 V, max =  +1.60 V)
+12V Voltage:       +11.58 V  (min = +10.20 V, max = +13.80 V)
+5V Voltage:         +4.92 V  (min =  +4.50 V, max =  +5.50 V)
+3.3V Voltage:       +3.31 V  (min =  +2.97 V, max =  +3.63 V)
CPU_FAN FAN Speed:  2428 RPM  (min =  800 RPM, max = 7200 RPM)
CHA_FAN1 FAN Speed: 1188 RPM  (min =  800 RPM, max = 7200 RPM)
PWR FAN FAN Speed:   546 RPM  (min =  800 RPM, max = 7200 RPM)
CHA_FAN2 FAN Speed: 1066 RPM  (min =  800 RPM, max = 7200 RPM)
CPU Temperature:     +35.0°C  (high = +60.0°C, crit = +95.0°C)
MB Temperature:      +38.0°C  (high = +45.0°C, crit = +95.0°C)

Can somebody recommend me what to do next?

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EDIT: I've used another power supply unit (be quiet BQT E5-450W) and the freeze still occurs.

EDIT 2: I've replaced every part except for the mainboard and the cpu. As I cannot find a motherboard which uses ddr2, pcie3 with an intel lga 755 socket I choose the lazy way and bought a new computer...

Answer 1

When I have that problem. It is 99% of the time because the CPU overheats. It might not show on psensor. The first thing I always do is removing the heatsync. Cleaning the CPU and the bottom of the heatsync of the thermal compound. And put some new thermal compound on the CPU. Put back the heatsync. And the problem is fixed 99% of the time.