From click here
If flashed with the right bios version, all board versions support Duron Spitfires, Duron Morgans, Athlon Thunderbirds*, Athlon XP Palominos and Athlon XP Thoroughbred A/Bs based on a 100 (200DDR) or 133 (266DDR) FSB. The board also unofficially supports the Athlon XP Barton, but you will not be able to boot the board at the Barton's nominal 166 or 200 MHz FSB because of a hardware limitation, therefore you will have to either underclock your Barton or experiment with software FSB changing to run it at 166MHz FSB.
In other words, you can put up to an Athlon XP 2400+ or an Athlon XP 2600+ (only the 266FSB version) on the K7S5A.
I've run a XP2000 with this board, just make sure you have a good heatsink & fan combo as it seemed to run hot