Not necessarily- thats a good sign that it originally identified itself correctly.
233mhz CyberstormPPC cards have an infamous low tolerance to heat- have you tried the WarpOS patch:
Change ENVARC:PowerPC/No233Fix to 0 (enables patch)
Change ENVARC:PowerPC/No233Fix to 1 (disables patch)
Restart Amiga.
Of course extra cooling is preferable- the standard 5v fan may need upgrading to a 12v variety.
Also make sure that there is sufficient (+not too much)
thermal compound between the PPC and heating and the fan is clean and rotating well.