"By the way, someone give me a reason to switch between, rather than just choose, 6x or 12x mode. VALID, please, I am sure that no semiconductor manufacturer would care about "I only have one and I want to experiment" or such."

1. Manufacturer makes one product that is usefull for 6x (faster operation) and 12x (most compatible). And the atmel product is 12x out of reset, so it compatible without fiddling with any registers or parallel programmers.

2. Philips requiring of a parallel programmer to change a parameter on an "ISP" chip is rather awkward, isn't it ?

3. From your other post, the "66x" does not have 8k !. The 668 does. The 664 and 662 do not.

I would say that Atmel did more than they had to in some areas to make the RD2 useful, and Philips did less than they should have, but both products are useful.