[roders]

I think on the first rev intel MacMini's the socket (M) for the Intel Core processors was (had) 479 pins, but I think the latest 4MB cache Intel Mobile (socket M) Core 2 Duo processors actually use a 478 Pin configuration (not to be confused with the P4 478 Socket ! ).
Just wondering which socket (M) my 2nd version (i.e. combo drive base version) 1.66Ghz Core Duo MacMini has, 479 or 478 (socket M) in case I want to upgrade the CPU, to say a C2D T7700 future price (coming down) permitting.

[Simon]

Yours has a socket M. All Intel Mac minis (including the current models) use socket M.

Socket M Meroms:
T5500 - 1.66 GHz / 2 MB / 667 MHz
T5600 - 1.83 GHz / 2 MB / 667 MHz
T7200 - 2.00 GHz / 4 MB / 667 MHz
T7400 - 2.16 GHz / 4 MB / 667 MHz
T7600 - 2.33 GHz / 4 MB / 667 MHz

No Mac mini so far has gone socket P Merom (SR refresh) or Penryn. Likewise, the chipset is still Calistoga and not yet Crestline. This will certainly change when the new Mac mini is launched, but nobody really knows when that will be.

BTW just FTR, both socket M and socket P have 478 pins. Just like the "Socket 478" the P4 used. The same number of pins does not mean they're compatible though.

[mduell]

Don't expect the price for old CPUs to fall... newer chips will come out that are faster and cheaper, but once a chip has been deprecated the price usually stays the same; the final price drop may coincide with the release of the new chips.

You're better off buying a new Mac mini when they're updated and selling your current one.

[Simon]

Originally Posted by roders 

Just wondering which socket (M) my 2nd version (i.e. combo drive base version) 1.66Ghz Core Duo MacMini has, 479 or 478 (socket M) in case I want to upgrade the CPU, to say a C2D T7700 future price (coming down) permitting.

You want a T7600 (or T7400), not a T7700. The latter is socket P.