"There will come an end to the core-count wars. I won't put an exact date on it, but I don't myself expect to see 128 cores on a full-sized server die by the end of this decade. It is not unrealistic from a technology road map, but from a deployment road map, the power constraints that people expect [servers] to live in" wouldn't be feasible for chips with that many cores, Donald Newell, AMD's chief technology officer for servers, told PC World.
Newell compares the core-count wars to the frequency wars, which ended recently. Improvements in CPUs were measured largely by clock speed, with each new generation of processors sporting "more and more GHz." Eventually chip companies realized that chips simply got too hot and increasing clock speed indefinitely just wasn't possible.
The solution was dual-core server and desktop chips, followed by quad-core, six-core, and eight-core options from both AMD and Intel. It will end someday, but how many cores will be claimed as the optimal number?