Linux tends to have better driver support, so if it's running in Linux, it doesn't mean it will run in FreeBSD, (especially with newer Intel cards, but that's another story). The 346 or newer driver should work though.
I've had similar situations, where it seems to see the card, the right driver is installed, but X won't start. In my case, I've always had access to other video cards that work, (and these cards would work with a different motherboard), so I've never done a thorough investigation.
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