A) Just for clarification. The Xeon 3060 and the equivalent desktop variant, i.e. Intel Core 2 Duo are not architecturally identical.
If you were to open these chips up and look at the transistor locations within their physical design you will notice that their positions are not identical, and there are a few different transistors within the Xeon, than there are with the Core 2 Duo.
As for architectural changes, yes there are changes and differences between both. These have been both confirmed with me and some engineers I have spoken to with Intel. These implemented changes will allow mathematic speeds to increase slightly over time, and therefore the chip itself will be able to perform mathematics at a faster rate over a long period of time.
In SPEC2000, running a 4 hour test for 32 Integer Floating Point, the X3060 completed the task 4.8% faster than the Core 2 Duo E6600. Whereas the Core 2 Duo E6600 completed the Direct3D test faster, by 2.9%.
Please do not state "opinions" if you are unable to back it up. I have just backed up this information from my first hand testing, and with personnel at Intel Fabrication
B) The memory sub-system is extremely powerful, and will operate correctly until at least 1150MHz (personally tested). The only problem is with the 1:1 ratio sub-systemwhere there are problems. As soon as you change to a 4:5 ratio, for example, there will be no issues at all with memory (which relates to the board).
C) I do not know what you have done wrong but the X3060, even revision A, will surpass 450MHz FSB, if system components will support this frequency. I suggest you try different options to ascertain this clock frequency.
Anyhow, congratulations on your overclock