I'm currently testing for my FSB limits on my CPU/mobo right now using Orthos as described here:

FSB Testing

We'll be using Orthos for this testing, so please be sure to have that installed before hand.

Go to the BIOS.
Go to uGURU Utility.
Set DRAM Speed to 1:1.0.
Multiplier Factor should still be at the lowest number.

External Clock. Just like with the memory, we'll start increasing this value to find our FSB max. 400MHz should be a doable, so we can start here and move up in increments, or you can skip straight for what you guess the top FSB might be and start working your way down if failures are encountered.

If Windows loads up okay, then we are off to a good start. Now launch Orthos and run the Blend test. I'll run that for 20 minutes. If successful, stop the test, restart the computer, go into the BIOS, uGURU and increase the External Clock by 10MHz and retest for another 20 minutes.

If there are any errors with Orthos, reboots, failure to load Windows, or failure to POST, then you can go into Voltages Control and increase the MCH voltage a notch. If there are still problems, then increase the ICHIO voltage a notch. And finally try increasing the CPU VTT voltage. You may try two or three notches.

If after 4 notches increases in the voltage and there is still no stability, you may have to lower the External Clock and reset the voltages back to defaults and test again with the lower External Clock.

Your CPU may also have an FSB limit as well that could be encountered before your motherboards FSB limit.
My question is: what priority level in Orthos (from 1-10) should I be using? Also, which priority level should I use when I'm testing overclock stability later on? Thanks in advance.