I think the SECC1 design was more based on practicality of cache that was available at the time; While the connector was 'proprietary,' the Bus design itself wa

I think the SECC1 design was more based on practicality of cache that was available at the time; While the connector was 'proprietary,' the Bus design itself was probably a more protect-able part of locking AMD out. FWIW AMD's original Athlon used a Slot connector as well, for similar reasons.