Intel’s new LGA 1156 CPU socket is smaller than LGA 1366, and as a result the CPU heatsink mounting holes are 3mm closer together. While this will reduce the amount of flex in the motherboard when the heatsink is mounted it also means that a new heat sink mounting system is needed. Intel has developed their own CPU cooler that will come with retail boxed processors and it is tiny!
The aluminum fins stand just 0.75″ tall, which should give you an idea of just how thin this heat sink really is.
First up to bat is the Intel Core i5 750 processor and at idle the CPU temperature with the retail boxed CPU cooler was observed at being 39C.
Firing up Prime95 and running the blended test we were able to get the CPU up to 74C in just a matter of minutes! This is pretty hot and even the ASUS TProbe v10007 alerted that the temperature was hot, so it will be interesting to see how the Core i7 870 does on the same CPU cooler.
The Intel Core i7 870 processor ran at 40C when at idle with the retail boxed CPU cooler. This is actually fairly nice considering the Intel Core i5 750 was running at 39C. Keep in mind that both processors idle at the same clock frequency and base clock, so it should be similar.
While the two processors had similarities at idle the Intel Core i7 870 processor ran much hotter at full load with the retail boxed CPU cooler. The Intel Core i7 870 actually hit 91C before we aborted the test due to how high the temperature got under full load. The Lynnfield processors are good news for after market CPU cooler manufacturers as not many enthusiasts and gamers will want to see their processors reaching over 70C at load.
Intel also sent over the Thermalright MUX-120 heatsink for testing, which really helped improve thermal performance on the Intel Core i7 870 processor. The temperature dropped from 40C to 32C at idle and from 91C to 64C at full load under Prime95 by just moving over to the Thermalright MUX-120 CPU cooler. This is the cooler that we stuck with for testing as it provided adequate cooling for both the Core i5 and Core i7 Lynnfield processors.