Thanks for your summary and links. I did the first timing fix and everything seems quite stable! :-)
@Retrofan: sorry for not stating it clearly - not because of the CF-card, but the CF-card works nicely in the newly stable configuration :-)
I am still hesitating with the second because I'm not entirely sure whether it applies only to certain revisions of the motherboard (1D.4 is mentioned
) or if ones experiences graphics-corruption/ noise?
Wisdom is of course not trying to fix something that is not broken (possibly inviting problems), but if it only can help and when soldering is a joy why not?