Altho the question has been asked over and over.. and some people get pissed at such redundancy... we HWC members are more than willing to help out still! right guys? hehe
anyways, back to your questiosn. I have the exact same things you have, BP6 and C400.
the only things you have to consider in the softmenu are:
1. CPU Speed = User defined
2. Turbo = Off
3. External Clock = FSB speed, for 550 you need 92 FSB (92 x 6 = 552)
4. Multiplier = 6 (Do not change this!)
5. AGPCLK/CPUCLK = 2/3. (i.e. 92 x 2 / 3 = 65Mhz)
6. Speed Error Hold = Disable
7. CPU Voltage 1 = 2.0 (If it doesn't boot into Win try increment .5V at a time)
8. CPU Voltage 2 = 2.0 (Only if you have a seoncd CPU)
CPU Speed = FSB x Multiplier.
400Mhz (Default) = 66Mhz x 6
450Mhz = 75Mhz x 6
498Mhz = 83Mhz x 6
552Mhz = 92Mhz x 6
600Mhz = 100Mhz x 6
For your AGPCLK/CPUCLK, always use 2/3 so that it runs close to 66Mhz. Unless your AGP card can support higher speed without exploding.. hehe.
Sterling, your link said what I would never take time to explain to most folks. I have often wished someone would host a site with information about specific BIOS settings for specific motherboards. Hell, I could do it myself if I had a stack of current manuals for the most popular motherboards. There simply can't be more than 50 boards out there in use by 99% of everyone reading these posts. If we all sent a copy of the BIOS options to HWC or a volunteer, perhaps(please,God, not me), then it would make the job easy. It would generate a HUGE number of hits, take my word for it. My silly site could go commercial and I don't even mention any BIOS settings.
P4 email@example.com dual R134A phase change chillers with 600watt thermoelectric array. Capable of -70F
Nixie tube numeric display control panel and pneumatic motherboard tray.
I can't take credit for the above article, it was written (and very well written I might add) by a friend I met online at Ars-Technica named Apex. He is one of the most helpful overclockers you could ever find.