Nah that's a rumour. It wouldn't help nV to do that as their board makers would drop them like a stone an take VIA instead. The small performance gain wouldn't be worth that kind of of compatibility bug.
The early rumours are false. The only problem they have is the same as the early KT400 VIA boards that had trouble with 8X support for both the GF4ti and the R300(9700/9500) series.
Seriously nV knows that if this got out that their next board, the nForce3 (which is turning in poor numbers against the VIA KT800) would get passed over by people who want tha ability to put whatever they want in their rigs. This would be like them specifically going out of their way to disable Creative Audigy cards to shore up their onboard solution and pave the way for their own add-in cards later.
Making something work BETTER, would make sense, but hampering any add-in card would simply hurt the relatively immature nForce line (remember this is the succesor to the nForce (1) chipset which wasn't the star the nF2 is, so they really wouldn't benifit from building in another bug to continue the idea that they can't make a good board.
The nForce2 may be a flash in the pan, we'll have to see what the next version of nForce3 does, and the (nForce5?) pentium chipsets still have to prove themselves.
But for your immediate questions, any recent nForce board will work fine with those cards, and even the old boards wouldn't favour one or the other, it would just have problems with both.
BTW, there were also memory issues early on as well. Get a recent version of the board and you can be pretty sure it'll do just fine.
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