Average idle temperature for i7 965 Nehalem 1366?

Just wondering what should be the average idle temperature should be for an i7 965 Extreme Edition Nehalem 1366 processor.

The thing is, ever since the first day I bought and assembled this computer, my average idle temps have been between 45-50 C, and this is with a Zalman 9900LED, which is supposed to be a pretty decent heatsink. On 100% load with Prime95's Blend test running, it goes up to 75-80C and stays there.

Today, as part of some maintenance, I cleaned out the dust that was caked onto the Zalman, cleaned out and reapplied thermal paste to the CPU. I thought that perhaps if I did this it would help with the temps, but the temps have remained roughly the same.

I have no air conditioning - we live in a fairly humid place where average temps are around 27-29C with 60-70% humidity. I'm not sure if the ambient temperature is a significant part of the problem, but I'm reading forum posts here that say that my average idle temps should be 35-40C, about 10 degrees cooler than what my idle temps are.

I'm using an Antec 1200 for my case, which is supposed to have great airflow. I'm getting these temps without any overclocking, so I'm wondering if I'm just applying the thermal paste wrong, or if I'm missing something blatantly obvious.

From what I can find out, your CPU will be happy and long-lived at anything less than 105 C.

Average idle temperatures do depend on ambient temperature, as well as specific case and cooling system design as well as settings that affect how the cooling system responds to changes in (e.g fan speed settings).

No CPU is ever completely idle (unless in a halted state), it's "idle" workload depends on a lot of background tasks that vary a lot depending (amongst other things) on the version of the operating system and the peripheral drivers installed.