http://www.everymac.com/upgrade_cards/sonnettech/encore_g4/encore_g4_1.0.html
This site says there are 2 versions of that CPU, one for Beige G3's only and one for beige and B&W G3. Since the card runs at 66 FSB the original version might not boot on a 100 FSB machine. Stick it in a Beige G3 and see if it boots.
This site says there are 2 versions of that CPU, one for Beige G3's only and one for beige and B&W G3. Since the card runs at 66 FSB the original version might not boot on a 100 FSB machine. Stick it in a Beige G3 and see if it boots.