I am planning to update by household server. Though it does very little other than serve files, it is on 7/24 so minimizing power consumption is a highly desired feature. To this end, I was thinking about building up a system using the Intel Core 2 Duo T7100 (or some other processor in the Merom-2M family).
The problem is this - I cannot find a motherboard than accepts this processor. According to http://en.wikipedia.org/wiki/List_of_Intel_Core_2_microprocessors, the sockets used by the family are either Socket P or Socket FCBGA6. Are there any desktop-type motherboards that use this socket? Are there adapters that allow using this chip in a LGA 775 socket? Can you offer any other suggestions regarding a low-power machine?
You can get a significantly cheaper processor with similar (or even lower) power consumption to run a file server off of. VIA's C7 and C7-m (both are X86 cpu's) processors are cheaper, passively cooled, and consume less than 20 watts at 100% utilization. The C7-m uses even less power, though I don't recall the specifics. Either one is more than sufficient to run a file server.
If VIA doesn't do it for you, a Sempron or (gag!) Celeron would both be cheaper than a Core 2 and run at or below the power usage of the Core 2. They are also overkill for the CPU needs of a file server, but not as much overkill as a Core 2.
VIA C7's usually come embedded in a motherboard, so they cannot be changed out. There are also very few manufacturers who produce them and sell them in the retail channels. I think NewEgg has some in stock though.
The Semprons and Celerons are easy to find motherboards for.
As far as your C2D T7100, if you are married to the idea, I can't help you. Motherboards with sockets for mobile processors are few and far between.
I'd go for an am2 dual core 2350 which is 45 watts. Newegg has them for $89. They also have a biostar agp board for $38 after rebate, but I don't remember the model number. The socket 754 turions are also available for around $140 (25 watt). Msi boards will run them.
groston: did you go ahead with the t7100? If so, did you manage to find any modt(mobile on desktop) style motherboards that will accept it?
I just bought myself a t7100 along with an abit il90mv thinking that it would fit; unfortunately i have only just then found out that the abit m/b takes socket m cpu's, while the t7100 requires a socket p! aaargh