I bought "ECC" ram for my MacPro1,1 but system reports only shows FB-DIMM
It's not showing as ECC because it's not ECC.


  According to Wikipedia, most Registered ("Buffered") RAM is also ECC,
  it isn't always the case.


That's not exactly correct.  Registered memory has ECC functionality, but not all ECC is registered.  Kingston goes on to explain the difference in the FAQ:  What is the difference between registered, unbuffered, ECC and fully buffered memory? 

Secondly, the memory you specified, the Kingston F51272F51 is not listed anywhere as being ECC.  It is listed as being Fully Buffered, however.

Finally, looking at the "supported systems" for this memory on Kingston's website, Apple is nowhere to be found.  So, while is technically works, it's not "correct."



Unfortunately, what you purchased on eBay was not accurately described.  The actual memory that you need from Kingston is KTD-WS667