I just paid 10 GBP's for a G3 zif socket CPU (ebay, UK) for my beige G4. I want to "downgrade" its Sonnet G4 to an original G3 CPU pulled from a beige.
Received my G3 cpu zif today. SIX DAYS since purchase from the UK to here in Oz! Local mail isn't this good at times 
Swapped out the Sonnet and Yes! It works just great. Fast and feels like it should, as an actual beige G3, 300MHz.
Anyone needing a used Sonnet G4 400MHz ZIF cpu? Going cheap 
