When overclocking an AMD Phenom II X4 965 Black Edition CPU is it safe to exceed AMD’s spec of a maximum processor temperature of 61°C by a little way?

PROBLEM: I have read that processors [CPUs] can run safely at up to 80°C but that when overclocked or otherwise the temperature should be kept below 60°C. My desktop PC has an AMD Phenom II X4 965 Black Edition processor, which has a high level of overclocking potential, and a Scythe Katana 3 air cooler. The AMD Overdrive utility has allowed me to overclock it from its stock speed of 3.4GHz up to 4.0GHz. The CoreTemp utility reports temperatures in the high fifties, occasionally peaking at 63°C. Although, when at that temperature the PC works perfectly, I am worried because AMD’s spec for the CPU’s maximum temperature is 61°C. CoreTemp also reports that the “Tj Max” for the processor is 90°C. Should I return the processor to its stock speed of 3.4GHz?

ANSWER: The 80°C figure is a common generalisation. There shouldn’t be any damage to the CPU at that temperature. Laptop (mobile) processors don’t usually have a maximum temperature under 100°C. That said, not all desktop processors would run faultlessly at 80°C. The 90°C Tj Max is the temperature that no part of the processor should exceed. The rule of thumb is that the temperature shouldn’t get to within 20°C of it, which would be 70°C.

It would probably be safe to run the CPU at 70°C, but it is not advisable to exceed AMD’s stated 61°C maximum for long periods, so removing the overclocking would be a sensible unless you need the extra performance for, say, gaming. Running a CPU at a 100% load is a worst-case scenario, since very few computing activities make the maximum demand. Your CPU just goes a few degrees above the recommended maximum, so I would implement a modest overclock and have CoreTemp running while using the PC under usual conditions, viewing what the maximum recorded core temperature is from time to time. If it remains below 61°C, increase the overclocking, which could also entail increasing the system bus speed, upping the clock-multiplier setting and increasing CPU’s operating voltage in the system BIOS. However, if the recommended maximum of 61°C is approached in normal use, improve the system’s cooling. Get a better heatsink and fan cooling unit and add case fans, remembering that you have to get the air flowing through the case, usually with the fan(s) in the front pulling air into the case and the fan(s) at the back extracting it.

There should be at least one fan drawing air into the case and at least one fan expelling air. Using a powerful graphics card, usually makes it necessary to add case fans. Make sure that the cabling inside the case is as neat and as far out of the airflow as possible and don’t put the PC in a confined space or near sources of heat.

Using a water cooler would allow the maximum overclocking if air cooling fails to make the PC run under 61°C. At the time of writing, the following video was available showing such a unit and how it is installed. I would search Amazon for Liquid CPU Coolers. I saw a few well-reviewed models made by Corsair when I used that search query.

Kuhler H2O 620 Liquid Processor Cooling System Installation


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I am an experienced PC technician who has been the owner and sole writer of the PC Buyer Beware! website since 2004. I am learning all the time in this very dynamic, ever-changing field.