My N900 has been overclocked to 1150 mhz and running stable for months. The minimum clock speed is 500 mhz.

Today I reset the clock speed. The maximum is still the same 1150 mhz. But I set the minimum clock speed to 1000 mhz. Now my N900 runs much faster. I have never seen the e-mail program open so fast!!! (we'll see if it melts.)

Question is... why? If the max clock speed was previously set at 1150 mhz then why didn't it speed up when I gave it something intensive to do like load all my e-mail accounts?

What controls when the cpu decides to speed up or slow down?

You probably will damage your phone. Mine is running at 500 mhz minimum and 720 mhz maximum and its running very smooth. and yes if you want you N900 to be stable and smooth even with default minimum and maximum mhz's then upgrade your N900 to CSSU-Thumb and then see the magic.

Thanks for the tip about CSSU-thumb.

I'm quite sure a clock of 1000-1150 will damage my 900.

But my main question is more like this:

My clock is 500-1150 and my cpu is running ~90% opening email and web pages... but it is only at 800mhz. It *could* be at 1150 but it doesn't go. Why?

They are triggered by cpufreq's governor that changes the CPU frequency depending on CPU utilization. This is called "ondemand".

The reason there is less lag is that from idle your device jumps to the first frequency then upwards via ondemand.

You are pretty much guaranteed to damage your device at anything above 805Mhz. Thumb and a Smartreflex enabled mild-overclock would be considerably better in long run.