Just a recurring question in my mind that won't go away.

I've fortunately been able to acquire a few Voodoo 5 5500s recently and it seems that Hyundai chips are the most common, but one uses Samsung (the Voodoo 5500 PCI), and I've seen images of others with Toshiba chips. Is there a story here? Were these chips more or less the same and were just randomly sourced as needed during manufacturing? Are some more sought after than others (overclocking?)?