(18665) - What are the jumpers on the SpeedStar A90 / Stealth III S540 / S540 Xtreme for?
These jumpers determine what AGP mode the S540 will run at. The default setting for the jumpers is AGP 1X/2X, and these do not need to be changed unless you have an AGP 4X capable motherboard. Consult your motherboard documentation for information on what your motherboard is capable of.
Please refer to the addendum included with the card for specifics on the jumper settings.
The above is from the FAQ at
Diamond. I forgot to copy the exact url.
I downloaded the pdf and it says to close JP1, JP2, and JP3. From the looks of what I read, you're probably out of luck as far as 4X working on your Athlon system.