"Core Temp" - CPU Temerature monitoring tool

[unclewebb]

The only CPUs I've found that the whitepaper method doesn't work on is the Atom line because the timers in MSR 0x30A and 0x30B are not functional. There might be some Core 2 ES CPUs with the same problem but I haven't heard of any. Correction: I forgot. There was one user a long time ago with a QX6700 ES that didn't have these timers.

This method works great on all of the Core 2 CPUs that I've tested. The QX is a bit of an odd ball because the base multiplier can change depending on what multiplier you set in the bios. As you know, on all of the newer Core i CPUs, the base multiplier is fixed and it is easy to read the base multiplier from a register.

With the QX you need to check MSR 0x17 for the base multiplier. If the multiplier in the EDX register of MSR 0x198 is less than the multiplier in MSR 0x17, you have to use the lower value in MSR 0x198 as the base multiplier.

For the rest of the Core 2 CPUs, the base multiplier is in EAX of MSR 0x17. Once you have this, you multiply by the ratio that the two timers are running at and you have an accurate value for the multiplier. The advantage of this method is that it can correctly detect Intel Dynamic Acceleration which Intel uses on a lot of their mobile Core 2 CPUs. It also detects SLFM very accurately. The method is more accurate on a Core 2 CPU at idle compared to the traditional method of reading the EAX register of MSR 0x198. At full load when a CPU does not support IDA, both methods should be the same.

If you use this method for Core i then consider using it for Core 2 as well. The white paper method is a little complicated but it provides users with the most accurate look at what their CPU is really up to.