G3 upgrade cards unstable?

According to a MacWEEK article: "An incompatibility between the PowerPC 750 (G3) processor and the ROMs in PowerPC 604-based systems can create serious system instability, and the consequences range from nonfunctioning I/O cards (e.g. SCSI, video) to complete system crashes. In extreme cases, the instability may damage or destroy the data stored on a user's hard drive."

MacFixIt reader Hong Nguyen recently confirmed one instance of this problem, noting he could not get his OrangePC 620 card to work after installing a Sonnet G3/300 card in his Power Mac 8500 (an ATI XClaim 3D card may also be involved).

This G3 card issue was also raised in a letter from the CEO of Newer Technology (covered here previously). In both the letter and the MacWEEK article, quotes from Newer are inexplicably ambiguous. Newer cites a hardware fix that eliminates the problem on their cards. But they do not make clear what cards need the fix and what cards (if any) already have it. On the plus side for Newer, Dantz Development reported that Newer cards were the only ones that worked in their tests of a compatibility issue.

Representatives ofvarious other companies (e.g., Sonnet, PowerLogix, Mactell) differed in their assessment of the problem. Some claimed the problem was rare while others claimed it was common.various potential work-arounds were described.