This article expands on the popular article series Core i7 860 Overclocking, which extensively benchmarked the maximum overclock potential of the Core i7 860 using the stock cooler.
There was a lot of interest in voltage and maximum temperature for this chip. Obviously, no one wants to risk frying their expensive investment. The Core i7 860 and Core i7 870 use a 45nm fabrication process and possess a 95W thermal design power (TDP).
The smaller design and low power consumption are frontier country, even compared to their big brothers. The 900 series “Bloomfields”, which include 7 different CPUs, all have a 130W TDP. It makes sense to know whats safe and when you should start getting worried, like this disaster when you use ASUS Auto-Tuning.
Voltages and Temperatures
The following temperatures were read while the Core i7 was in a HAF922 case and a room temperature environment (72°F). All loads were created using Prime95. Your real-world experience will vary based on your ambient temperature and air flow.
You should recognize that achieving 100% load on a quad core is something that 99% people will never see. You can actually set the CPU voltage significantly higher and never get your temperature too high. For example, 1.3V on the stock cooling fan is feasible even for gamers. In those cases, there is not enough load on the CPU to heat it up. However, we’re talking about max safe temperatures, so no dice.
The maximum safe voltage below assumes Hyper Threading is turned off. In testing, there was a 20°C difference at 100% load. Hyper Threading is turned on by default, so you must change it in your bios. I recommend that everyone do this if you are not encoding high definition video content.
|Minimum Voltage||0.650V||Idle Temp (stock voltage)||35°C|
|Default Voltage||1.145V||Load Temp (stock voltage)||72°C|
|Maximum Voltage||1.400V||Tj max (shutdown) Temp||100°C|
|Max Safe Voltage (HT off)||1.150V||Max Safe Temperature||80°C|
Solid Tip: To keep the maximum temperature in a safe range, 1.150V is the maximum core voltage for the Core i7 800 series with stock cooling. Hyper Threading must be turned off if you benchmark your CPU at this voltage, or it will peak at 100°C!