Computer Weekly ran a story in late may, "Half of all new PCs fail 2000 BIOS test." Actually, the test reported that 47% failed, but that's close enough for government work. (I just thought: "government work" is an oxymoron.)
As for pre-1997 chips, up to 79% may not roll over. (The older they are, the more likely they will fail, or so it seems.)
Most PC makers use chips from multiple producers, so the fact that one brand of chip is 2000-compliant may not do much good.
PC makers told Computer Weekly that their 1997 machines are compliant.