I don't think the PPC upgrade for the Quadra PDS slots was all that common. Most of the ones I seen were bundles with AVID video editing systems (because of the need for a PPC Nubus system with more then 3 slots).
The Daystar 601-80 with 4 x 72 pin SIMMs and optional cache module is the one that makes the most difference to a 950 (and the cache and RAM can be used in 68K mode), but they are very rare and expensive. Cheaper to buy a PPC computer then to bother getting a 601 for the 950.
The Daystar 601-80 with 4 x 72 pin SIMMs and optional cache module is the one that makes the most difference to a 950 (and the cache and RAM can be used in 68K mode), but they are very rare and expensive. Cheaper to buy a PPC computer then to bother getting a 601 for the 950.