How We Tested

We tested mayonnaise as a thermal compound on a Core i5-2500K CPU (quad-core, 3.3 GHz), which is a socket LGA1155 processor with a 95 W TDP (Thermal Design Power). In order to get higher thermal dissipation, we overclocked it to 4.0 GHz (100 MHz base clock and x40 multiplier), with 1.3 V core voltage (Vcore). The cooler used was the Cooler Master Seidon 120XL, which we reviewed recently.

We measured the core temperature with the CPU under full load. In order to get 100% CPU usage in all cores, we ran Prime 95 25.11 with the “In-place Large FFTs” option. (In this version, the software uses all available threads.)

Room temperature measurements were taken with a digital thermometer. The core temperature was read with the SpeedFan program (available from the CPU thermal sensors), using an arithmetic average of the core temperature readings. During the tests, the panels of the computer case were closed.

We calculated the Delta-T (difference between the core temperature and room temperature) immediately after starting the test, at four hours, and at eight hours, and after that, we repeated the test once per day for 12 days.

Between the tests, the system was working continuously, running the [email protected] SMP client, in order to keep the CPU warm and stressed.

Hardware Configuration

Operating System Configuration

  • Windows 7 Home Premium 64 bit SP1

Software Used

Error Margin

We adopted a 2°C error margin, meaning temperature differences below 2°C were considered irrelevant.


Rafael Otto Coelho is a physicist, a PhD student, and is a college professor in Brazil.