A friend of mine who already owns two SX6000 wrote me about his "adventures" with his second SX6000 he is trying to use with a Iwill MPX2 motherboard. Here is what he noticed over the week-end:
If the video card is a Radeon 8500 with the SX6000 in a 32-bits slot, the BIOS won't post regardless of the network card.
If the video card is a Radeon 8500 with the SX6000 in a 64-bits slot and the network card is a 3Com, the BIOS will post.
If the video card is a Radeon 8500 with the SX6000 in a 64-bits slot and the network card isn't a 3Com, the BIOS will detect the SX6000 only one time out of twenty.
If the video card is a Matrox G550 with the SX6000 in a 32-bits slot and the network card is a 3Com, the BIOS will post.