This is a fascinating thread.
I have read most (but not all) of the thread and have the impression the SGM Extreme does not use a replacement precision clock on its motherboard (eg an OCXO or other type). This would seem quite unusual for an statement level PC server.
Can anyone clarify if this correct, or have I may have missed something in the long thread ?
Can any light be shed on the reason precision clock is not necessary ?
There are two factors at play, benefits from improved clock stability on CPU and thread execution performance and RF Emission signature from external clock, its power supply and cabling.
Clock stability is important for CPU process error rate reduction, but once the clocking has reached a certain level of timing performance, it is difficult to detect further improvement. Also Server grade motherboards have significantly better implementation of power supplies and clocking to keep CPU error rates low. Consumer grade CPU's and motherboards are optimized to deliver maximum CPU speed for the buck, with little regards for error rates. The SGM Evo actually uses cherry picked consumer grade CPU's for better performance and lower error rates
The RF emission of a well done OCXO and its sonic signature is definitely SQ adding and this nice signature was enjoyed on the original SGM 2015 and on the EVO. What Emile has discovered is how to replicate the well done OCXO sonics with other components for an even better sound. The harmonic textures which the Extreme delivers are at another level from the Evo
If I may use a cooking analogy, using an OCXO is a bit like adding MSG to a soup. You can achieve even better taste enhancement by other ingredients and not use MSG
