Replaced CPU, now problems.

[Denithor]

Swapped an i5-750 for the i3 in my main rig. Not overclocked, using stock Intel fan. Booted Windows just fine. Idle temps around 50C. Started encoding a movie with Handbrake, watched temps climb into low 90s. Then suddenly computer just turned off. And went into a revolt cycle, can see fans spin up momentarily and then stop. Constantly until I power it off.

Pulled the motherboard, tried on open desk, same thing. Pulled battery, no change. Reseated CPU, no change. Tried a different known good PSU, same. Pulled i5 and put back in i3, same. Tried with only 1 stick of RAM, nothing.

At this point I'm stumped. Any ideas to try?

 

[C1]

A guess is that a component on the MB is damaged. Probably something involving voltage/current management. When you installed the i5, hopefully it was done in accordance with the MB CPU voltage settings specified in the MB installation/setup manual. Otherwise, you might have damaged an electrical component.

 

[Icecold]

Swapped an i5-750 for the i3 in my main rig. Not overclocked, using stock Intel fan. Booted Windows just fine. Idle temps around 50C. Started encoding a movie with Handbrake, watched temps climb into low 90s. Then suddenly computer just turned off. And went into a revolt cycle, can see fans spin up momentarily and then stop. Constantly until I power it off.

Pulled the motherboard, tried on open desk, same thing. Pulled battery, no change. Reseated CPU, no change. Tried a different known good PSU, same. Pulled i5 and put back in i3, same. Tried with only 1 stick of RAM, nothing.

At this point I'm stumped. Any ideas to try?

Your temps were way too high, indicating most likely that the heatsink was not seated correctly(I can't imagine poor application of thermal paste letting it get that high, but anything's possible). Based on your troubleshooting, it sounds like your motherboard has failed; I would try another motherboard as my next step.

 

[Puppies04]

OP, reseating your CPU is not the cure for excessive temps. Reseating the cooler is, stupid question but did you remove the old tim from the CPU cooler and replace it with new TIM when you swapped CPUs because if you didn't this is probably your problem.

Also keep in mind if your "new" CPU is actually not brand new you may need to remove the old TIM that is stuck to that aswell, i.e make sure the cooler and the CPU are both clean before you purchase some new TIM and apply it. If you are unsure of the correct method of applying TIM see google or post back here.