Six weeks with Core 2 Duo

at the start of August, I upgraded my linux workstation to a Core 2 Duo system. One of the reasons I went with Core 2 Duo was the fact that it's supposed to run much cooler, and consume less power than other CPUs.

Attachment and retention of the heatsink is difficult. for a long time my CPU was idling at 42.5°C, which dropped to 36°C with a replacement heatsink, although in the process of fitting this, I noticed that the stock heatsink had become loose. The trick seems to be to turn the little retaining clips fully clockwise before you position the heatsink and push down on diagonally opposing pegs until you hear a click.

The chip is advertised with a voltage range from 0.8 to 1.3v, but in practice it never goes below 1.14v. Also, the frequency never drops below 1.6Ghz, from the maximum of 1.86Ghz. This seems like a very small drop. An AMD64 chip in another system here goes from 1.8Ghz (1.4v) to 1.0Ghz (1.1v), so a much greater drop (and a much greater saving in power obviously).

Under load, (two instances of the gimps torture test for one hour), the temperature of the CPU reached 42°C. When I was down in Brisbane last year with a render farm of 3.60 Ghz Pentium 4's, they would hit 60°C at full load in an air-conditioned office. That's about 35° above the ambient temp. This Core 2 Duo chip at full load is 16°C above the ambient temp. That's pretty impressive. What was even more impressive was that, when that test was going on, with both CPUs at 100%, I could browse the internet as normal and didn't really notice and slowdown at all. This may be more due to the highly pre-emptive kernel I run though. Plus I run Linux not Windows, and it's a little better about multiple CPUs.

To put this into perspective, the thermal envelope seems to be about the same as for a pair of 1Ghz PIII processors, but with far less electricity consumed and nearly twice the processor speed. The idling temperature is about the same and the max load temperature is the same.