Strange Cool 'n' Quiet behaviour...

Question

This is kinda odd. On my MSI K8N Neo Platinum, Cool 'n' Quiet works just fine when I'm running at 10x240 6:5 (FSB:RAM),. However, when I'm running at 8x300 3:2, the computer simply refuses to load Windows with CnQ enabled...it quits right before the login screen. At both settings, the CPU and RAM speeds are the same (2.4GHz and 200MHz respectively), and I've kept the timings, voltages, and HT multiplier (3x) the same in both cases.
I know it's not an issue with 300MHz FSB being too high, since with CnQ disabled I can easily boot at 315MHz and it'd be rock stable 24/7. So I'm stumped as to what could be causing the failures when CnQ is enabled with the second set of settings.  
BTW, system specs are in my sig (click the link), and I'm using the official 1.3 BIOS.

Answer 1

Tritium,
I was under the impression that cool and quiet and overclocking simply do not mix.
The fact that you could even get it to work at 240 is amazing to me.
At 240, what were your other boot settings (initial cpu mult and initial cpu voltage especially).
The reason why cnq and overclocking usually don't mix has to do with cpu voltage (though correct me if I'm wrong).  cnq works as follows. a tiny "cpu driver" installed in the OS communicates with the BIOS, at OS startup, to obtain a list of possible cpu states. Each cpu state is a combination of cpu voltage and a cpu multiplier.  For example, the states that I have on my non-overclocked 3200+ newcastle are something like (this is from memory so don't quote me):
11x (2.2 ghz), 1.5V
10x (2.0 ghz), 1.4V
9x (1.8 ghz), 1.3v
5x (1.0 ghz), 1.1v
Now, let's note that nowhere in the above states was there mention of HTT. Just cpu multipliers. It seems that cnq is *assuming* that HTT is kept at 200. But what happens when (for example) you bump HTT to 240?  Let's redo the above numbers. The key is that ghz changes, but cpu voltage remains the same. THAT IS THE KILLER.
11 x 240 (2.64 ghz), 1.5V
10 x 240 (2.4 ghz), 1.4V
9 x 240 (2.16 ghz), 1.3v
5 x 240 (1.2 ghz), 1.1v
Note that with HTT overclocked to 240, which cnq is ignorant of, it's trying to run at higher and higher ghz values, without being given correspondingly higher cpu voltages. For example: at stock, no overclocking, we have 2.2 ghz at 1.5V.
But with 240 HTT, we have one of the states being almost as high a ghz value (9x240=2.16ghz) yet only being fed 1.3v of juice. 1.3v is very likely not enough to safely run 2.16 ghz (to give just an example).
And all that gets magnified with HTT greater than 240.
That's my theory on why cnq and overclocking don't mix.
I very much hope I'm wrong, by the way.
What would help is if you could run cpu-z on your stable 240HTT system, and report the above values (cpu mult, htt, cpu voltage) for each state that cnq shifts between. (run a light, moderate, medium, and heavy cpu workload to get it to switch between states...but you probably already know that).
What values do you see? Let us know...I'm very interested to see what your cnq states are at 240HTT...thanks!