Campaign Enterprise will use one core for each mail sending thread. The management program can use a different core than the sending thread, it is really just up to the operating system on how it distributes the workload. Since up
Version 11 of Campaign Enterprise is still only 32-bit but it will work fine on a 64-bit machine. There is no technical benefit to Campaign Enterprise running in 64-bit because Campaign Enterprise should normally use way below the 4GB memory ability of 32-bit operating systems. Campaign Enterprise version 12 will have a 64-bit version, but it will not help performance but will help with compatibility of support files, etc.