There is no direct answer to this as this will depend on many factors. Having worked with thermo some things you should consider would be:
1.) What OS are you using? I assume some form of Unix (in my case debian).
2.) Assuming you are doing this for work/thesis I assume you have access to some kind of mainframe/cluster/supercomputer (lets face it 2 weeks worth of calculations are small), you will want to use a CPU with similar architecture. In my case this was CSC, in Finnland.
Going off a tangent here but assuming you have access to 2.) you might also look into GPU compute with CUDA. The gtx480 offers some tremendous power for a fairly low price and offers a great entry way of getting into this field.
You never mentioned a budget but I would go with the other recommendations. Both the i7-3770 and i3-3240 offer hyper threading which should be of benefit for you and offer aggressive turbos when single threaded.
If ECC memory is a must, you might have to step up to a workstation CPU.