865 GBF Random Freeze / Reboot

Config
Intel 3.0 Ghz HT 478 pin CPU (HT - Prescott)
Intel 865 GBF board
2 512 MB Simmtronics 400 Mhz DDR - in Dual channel Config
1 40 Gb Samsung HDD - ATA
1 80 GB Samsung HDD - ATA
1 Sony DVD Rom
1 LG DVD Ram
128 MB AGP nVida 4000 MX
100 MBps LAN Card - Realtech
Wifi 802.11g Card - Netgear
Frontech TV Tuner Card -- old not used.
Onboard Sound & Video.
450 W Power Supply - Root -
Thermally advantaged iBall Box - Cabinet fan is not on variable speed
but works from direct power supply connector.

System is 2 yrs old.

System reboots / Freezes at random intervals . Between 2 Mins to 4-5
Hrs
Has even shown this behaviour during Boot up.
These issues started 2 months back.

Diagnostics Done
Tried with madrake 10 / Win 2000 pro & XP pro. Similar Behaviour
Ran memtest 86 for 8 hrs - No errors detected - except for one reboot
in between
Used Si- Soft Sandra to run complete diagnostic suite all Ok
Burn in tests on Sandra - Sometimes Reboots / Freezes except that all
ok.
Flashed Bios with Latest update.
CPU temp in range od 42C (at boot time) to 67- 70 C while running -
Using Speedfan to diagnose speeds.
CPU Fan runs at 2650 RPM - Using Speedfan.
Speed Fan cannot change CPU Fan's Speed ( This is the major change from
before - eairlier the fan speed used to change as the cpu got hotter I
could hear the inreased speeds - Speed used to go upto 3500 rpm)
Checked with stripped down setup - Only one memchip / one hdd - all
other peripherals removed no effect.
Tried swapping components - have changed everything except the CPU &
Mobo - still have the issue with every combination possible.

Can anyone provide any hints ,clues , or some diagnostic on solving
this almost baffaling mystery.

Regards
Abhishek

Abhishek

I have a similar setup with the same board and CPU. My guess is that your problem is that the system is shutting down because the CPU is overheating. This CPU shuts down the system when it reaches just about 70 degrees C. From your data is looks like the temperature could easily reach 70 for a moment, which would be enough to shut down the system. To check this theory, go to System Properties, Advanced, Startup and Recovery Settings, and uncheck Automatically Restart. If you do that the computer will not restart after an automatic shutdown but will go to a blue screen with some meaningless code on it. If you are watching the temperature closely you will probably see that the shutdown occurs just after the temperature reaches 68 or 69 degrees. That is you sign that the shut down is due to overheating.

Things to check: CPU cooler and thermal grease; all your fans (my overheating was due to a failed power supply fan, so the power supply was overheating and causing everything else to run hot - the power supply fan does not report on Intel Active Monitor); and whatever software is running in the background. With luck you can reduce the load on the CPU so it does not overheat. If all else fails try turning off hyperthreading in the CPU settings in system configuration that you can access with F2 after POST.

By eliminating background software, installing a larger power supply, and installing a new CPU cooler I managed to keep my CPU temperature below the mid 60's. Not ideal but better than trashing the whole system.

Colin