Use the "Detect optimal frequencies" button. From there, you can try making changes, very slowly, in about 5 mhz increments. Each time you move the slider, use the "Test Settings" button. Teh nice thing about the overclocker software you get is, you CANT set it to a harmful setting. It wont let you exit the software with a new setting unless you test it. If the test fails, it resets your speed to the default. I have my 5900XT OC'd to 5900Ultra speeds, and it works beautifully. Make sure the overtemp alarm is enabled, so it warns you if it is going to get hot (mine doesnt). Click the box for "fan always on" and the one that says "apply these settings at startup". Enjoy!
P.S.
You have a 400mhz FSB, and you are using old PC2100 RAM? Is it in 1 x 512MB or 2 x 256MB configuration? Meaning, do you have 1 DIMM or 2 to get your 512MB total? I would seriously consider upgrading that RAM to some low latency PC3200 that matches your 400mhz FSB. The slow stuff you are using now basically means your possible 400mhz FSB is limited to 266mhz. You are giving up over 1GB/second of bandwidth with that older memory. If you cant afford to get 2 x 512MB and upgrade to a total 1GB of RAM, you should at least go with 2 new 256MB sticks of the PC3200. Get the lower latency RAM if you can afford it, but stay with quality names. Go generic on memory, get burned these days.
